Axiom II.-When a body in motion impinges on another body at rest, which it is unable to move, it recoils, in order to continue its motion, and the angle made by the line of motion in the recoil and the plane of the body at rest, whereon the moving body has impinged, will be equal to the angle formed by the line of motion of incidence and the same plane. So far we have been speaking only of the most simple bodies, which are only distinguished one from the other by motion and rest, quickness and slowness. We now pass on to compound bodies. Definition.-When any given bodies of the same or different magnitude are compelled by other bodies to remain in contact, or if they be moved at the same or different rates of speed, so that their mutual movements should preserve among themselves a certain fixed relation, we say that such bodies are in union, and that together they compose one body or individual, which is distinguished from other bodies by the fact of this union. Axiom III.-In proportion as the parts of an individual, or a compound body, are in contact over a greater or less superficies, they will with greater or less difficulty admit of being moved from their position ; consequently the individual will, with greater or less difficulty, be brought to assume another form. Those bodies, whose parts are in contact over large superficies, are called hard ; those, whose parts are in contact over small superficies, are called soft ; those, whose parts are in motion among one another, are called fluid.
LEMMA IV. If from a body or individual, compounded of several bodies, certain bodies be separated, and if, at the same time, an equal number of other bodies of the same nature take their place, the individual will preserve its nature as before, without any change in its actuality (forma). Proof.-Bodies (Lemma i.) are not distinguished in respect of substance : that which constitutes the actuality (formam) of an individual consists (by the last Def.) in a union of bodies ; but this union, although there is a continual change of bodies, will (by our hypothesis) be maintained ; the individual, therefore, will retain its nature as before, both in respect of substance and in respect of mode. Q.E.D.
LEMMA V. If the parts composing an individual become greater or less, but in such proportion, that they all preserve the same mutual relations of motion and rest, the individual will still preserve its original nature, and its actuality will not be changed.
Proof.-The same as for the last Lemma. LEMMA VI. If certain bodies composing an individual be compelled to change the motion, which they have in one direction, for motion in another direction, but in such a manner, that they be able to continue their motions and their mutual communication in the same relations as before, the individual will retain its own nature without any change of its actuality. Proof.-This proposition is self-evident, for the individual is supposed to retain all that, which, in its definition, we spoke of as its actual being.
LEMMA VII. Furthermore, the individual thus composed preserves its nature, whether it be, as a whole, in motion or at rest, whether it be moved in this or that direction ; so long as each part retains its motion, and preserves its communication with other parts as before.
Proof.-This proposition is evident from the definition of an individual prefixed to Lemma iv.
Note.-We thus see, how a composite individual may be affected in many different ways, and preserve its nature notwithstanding. Thus far we have conceived an individual as composed of bodies only distinguished one from the other in respect of motion and rest, speed and slowness ; that is, of bodies of the most simple character. If, however, we now conceive another individual composed of several individuals of diverse natures, we shall find that the number of ways in which it can be affected, without losing its nature, will be greatly multiplied. Each of its parts would consist of several bodies, and therefore (by Lemma vi.) each part would admit, without change to its nature, of quicker or slower motion, and would consequently be able to transmit its motions more quickly or more slowly to the remaining parts. If we further conceive a third kind of individuals composed of individuals of this second kind, we shall find that they may be affected in a still greater number of ways without changing their actuality. We may easily proceed thus to infinity, and conceive the whole of nature as one individual, whose parts, that is, all bodies, vary in infinite ways, without any change in the individual as a whole. I should feel bound to explain and demonstrate this point at more length, if I were writing a special treatise on body. But I have already said that such is not my object ; I have only touched on the question, because it enables me to prove easily that which I have in view.
POSTULATES
I. The human body is composed of a number of individual parts, of diverse nature, each one of which is in itself extremely complex.
II. Of the individual parts composing the human body some are fluid, some soft, some hard.
III. The individual parts composing the human body, and consequently the human body itself, are affected in a variety of ways by external bodies.
IV. The human body stands in need for its preservation of a number of other bodies, by which it is continually, so to speak, regenerated.
V. When the fluid part of the human body is determined by an external body to impinge often on another soft part, it changes the surface of the latter, and, as it were, leaves the impression thereupon of the external body which impels it. VI. The human body can move external bodies, and arrange them in a variety of ways.
PROP. XIV. The human mind is capable of perceiving a great number of things, and is so in proportion as its body is capable of receiving a great number of impressions. Proof.-The human body (by Post. iii. and vi.) is affected in very many ways by external bodies, and is capable in very many ways of affecting external bodies. But (II. xii.) the human mind must perceive all that takes place in the human body ; the human mind is, therefore, capable of perceiving a great number of things, and is so in proportion, &c. Q.E.D.
PROP. XV. The idea, which constitutes the actual being of the human mind, is not simple, but compounded of a great number of ideas.
Proof.-The idea constituting the actual being of the human mind is the idea of the body (II. xiii.), which (Post. i.) is composed of a great number of complex individual parts. But there is necessarily in God the idea of each individual part whereof the body is composed (II. viii. Coroll.) ; therefore (II. vii.), the idea of the human body is composed of these numerous ideas of its component parts. Q.E.D.
PROP. XVI. The idea of every mode, in which the human body is affected by external bodies, must involve the nature of the human body, and also the nature of the external body. Proof.-All the modes, in which any given body is affected, follow from the nature of the body affected, and also from the nature of the affecting body (by Ax. i., after the Coroll. of Lemma iii.), wherefore their idea also necessarily (by I. Ax. iv.) involves the nature of both bodies ; therefore, the idea of every mode, in which the human body is affected by external bodies, involves the nature of the human body and of the external body. Q.E.D.
Corollary I.-Hence it follows, first, that the human mind perceives the nature of a variety of bodies, together with the nature of its own.
Corollary II.-It follows, secondly, that the ideas, which we have of external bodies, indicate rather the constitution of our own body than the nature of external bodies. I have amply illustrated this in the Appendix to Part I.
PROP. XVII. If the human body is affected in a manner which involves the nature of any external body, the human mind will regard the said external body as actually existing, or as present to itself, until the human body be affected in such a way, as to exclude the existence or the presence of the said external body. Proof.-This proposition is self-evident, for so long as the human body continues to be thus affected, so long will the human mind (II. xii.) regard this modification of the body-that is (by the last Prop.), it will have the idea of the mode as actually existing, and this idea involves the nature of the external body. In other words, it will have the idea which does not exclude, but postulates the existence or presence of the nature of the external body ; therefore the mind (by II. xvi., Coroll. i.) will regard the external body as actually existing, until it is affected, &c. Q.E.D.
Corollary.-The mind is able to regard as present external bodies, by which the human body has once been affected, even though they be no longer in existence or present. Proof.-When external bodies determine the fluid parts of the human body, so that they often impinge on the softer parts, they change the surface of the last named (Post. v.) ; hence (Ax. ii., after the Coroll. of Lemma iii.) they are refracted therefrom in a different manner from that which they followed before such change ; and, further, when afterwards they impinge on the new surfaces by their own spontaneous movement, they will be refracted in the same manner, as though they had been impelled towards those surfaces by external bodies ; consequently, they will, while they continue to be thus refracted, affect the human body in the same manner, whereof the mind (II. xii.) will again take cognizance-that is (II. xvii.), the mind will again regard the external body as present, and will do so, as often as the fluid parts of the human body impinge on the aforesaid surfaces by their own spontaneous motion. Wherefore, although the external bodies, by which the human body has once been affected, be no longer in existence, the mind will nevertheless regard them as present, as often as this action of the body is repeated. Q.E.D.
Note.-We thus see how it comes about, as is often the case, that we regard as present many things which are not. It is possible that the same result may be brought about by other causes ; but I think it suffices for me here to have indicated one possible explanation, just as well as if I had pointed out the true cause. Indeed, I do not think I am very far from the truth, for all my assumptions are based on postulates, which rest, almost without exception, on experience, that cannot be controverted by those who have shown, as we have, that the human body, as we feel it, exists (Coroll. after II. xiii.). Furthermore (II. vii. Coroll., II. xvi. Coroll. ii.), we clearly understand what is the difference between the idea, say, of Peter, which constitutes the essence of Peter’s mind, and the idea of the said Peter, which is in another man, say, Paul. The former directly answers to the essence of Peter’s own body, and only implies existence so long as Peter exists ; the latter indicates rather the disposition of Paul’s body than the nature of Peter, and, therefore, while this disposition of Paul’s body lasts, Paul’s mind will regard Peter as present to itself, even though he no longer exists. Further, to retain the usual phraseology, the modifications of the human body, of which the ideas represent external bodies as present to us, we will call the images of things, though they do not recall the figure of things. When the mind regards bodies in this fashion, we say that it imagines. I will here draw attention to the fact, in order to indicate where error lies, that the imaginations of the mind, looked at in themselves, do not contain error. The mind does not err in the mere act of imagining, but only in so far as it is regarded as being without the idea, which excludes the existence of such things as it imagines to be present to it. If the mind, while imagining non-existent things as present to it, is at the same time conscious that they do not really exist, this power of imagination must be set down to the efficacy of its nature, and not to a fault, especially if this faculty of imagination depend solely on its own nature-that is (I. Def. vii.), if this faculty of imagination be free.
PROP. XVIII. If the human body has once been affected by two or more bodies at the same time, when the mind afterwards imagines any of them, it will straightway remember the others also. Proof.-The mind (II. xvii. Coroll.) imagines any given body, because the human body is affected and disposed by the impressions from an external body, in the same manner as it is affected when certain of its parts are acted on by the said external body ; but (by our hypothesis) the body was then so disposed, that the mind imagined two bodies at once ; therefore, it will also in the second case imagine two bodies at once, and the mind, when it imagines one, will straightway remember the other. Q.E.D.
Note.-We now clearly see what Memory is. It is simply a certain association of ideas involving the nature of things outside the human body, which association arises in the mind according to the order and association of the modifications (affectiones) of the human body. I say, first, it is an association of those ideas only, which involve the nature of things outside the human body : not of ideas which answer to the nature of the said things : ideas of the modifications of the human body are, strictly speaking (II. xvi.), those which involve the nature both of the human body and of external bodies. I say, secondly, that this association arises according to the order and association of the modifications of the human body, in order to distinguish it from that association of ideas, which arises from the order of the intellect, whereby the mind perceives things through their primary causes, and which is in all men the same. And hence we can further clearly understand, why the mind from the thought of one thing, should straightway arrive at the thought of another thing, which has no similarity with the first ; for instance, from the thought of the word pomum (an apple), a Roman would straightway arrive at the thought of the fruit apple, which has no similitude with the articulate sound in question, nor anything in common with it, except that the body of the man has often been affected by these two things ; that is, that the man has often heard the word pomum, while he was looking at the fruit ; similarly every man will go on from one thought to another, according as his habit has ordered the images of things in his body. For a soldier, for instance, when he sees the tracks of a horse in sand, will at once pass from the thought of a horse to the thought of a horseman, and thence to the thought of war, &c. ; while a countryman will proceed from the thought of a horse to the thought of a plough, a field, &c. Thus every man will follow this or that train of thought, according as he has been in the habit of conjoining and associating the mental images of things in this or that manner.
PROP. XIX. The human mind has no knowledge of the body, and does not know it to exist, save through the ideas of the modifications whereby the body is affected.
Proof.-The human mind is the very idea or knowledge of the human body (II. xiii.), which (II. ix.) is in God, in so far as he is regarded as affected by another idea of a particular thing actually existing : or, inasmuch as (Post. iv.) the human body stands in need of very many bodies whereby it is, as it were, continually regenerated ; and the order and connection of ideas is the same as the order and connection of causes (II. vii.) ; this idea will therefore be in God, in so far as he is regarded as affected by the ideas of very many particular things. Thus God has the idea of the human body, or knows the human body, in so far as he is affected by very many other ideas, and not in so far as he constitutes the nature of the human mind ; that is (by II. xi. Coroll.), the human mind does not know the human body. But the ideas of the modifications of body are in God, in so far as he constitutes the nature of the human mind, or the human mind perceives those modifications (II. xii.), and consequently (II. xvi.) the human body itself, and as actually existing ; therefore the mind perceives thus far only the human body. Q.E.D.
PROP. XX. The idea or knowledge of the human mind is also in God, following in God in the same manner, and being referred to God in the same manner, as the idea or knowledge of the human body.
Proof.-Thought is an attribute of God (II. i.) ; therefore (II. iii.) there must necessarily be in God the idea both of thought itself and of all its modifications, consequently also of the human mind (II. xi.). Further, this idea or knowledge of the mind does not follow from God, in so far as he is infinite, but in so far as he is affected by another idea of an individual thing (II. ix.). But (II. vii.) the order and connection of ideas is the same as the order and connection of causes ; therefore this idea or knowledge of the mind is in God and is referred to God, in the same manner as the idea or knowledge of the body. Q.E.D.
PROP. XXI. This idea of the mind is united to the mind in the same way as the mind is united to the body. Proof.-That the mind is united to the body we have shown from the fact, that the body is the object of the mind (II. xii. and xiii.) ; and so for the same reason the idea of the mind must be united with its object, that is, with the mind in the same manner as the mind is united to the body. Q.E.D. Note.-This proposition is comprehended much more clearly from what we have said in the note to II. vii. We there showed that the idea of body and body, that is, mind and body (II. xiii.), are one and the same individual conceived now under the attribute of thought, now under the attribute of extension ; wherefore the idea of the mind and the mind itself are one and the same thing, which is conceived under one and the same attribute, namely, thought. The idea of the mind, I repeat, and the mind itself are in God by the same necessity and follow from him from the same power of thinking. Strictly speaking, the idea of the mind, that is, the idea of an idea, is nothing but the distinctive quality (forma) of the idea in so far as it is conceived as a mode of thought without reference to the object ; if a man knows anything, he, by that very fact, knows that he knows it, and at the same time knows that he knows that he knows it, and so on to infinity. But I will treat of this hereafter.
PROP. XXII. The human mind perceives not only the modifications of the body, but also the ideas of such modifications. Proof.-The ideas of the ideas of modifications follow in God in the same manner, and are referred to God in the same manner, as the ideas of the said modifications. This is proved in the same way as II. xx. But the ideas of the modifications of the body are in the human mind (II. xii.), that is, in God, in so far as he constitutes the essence of the human mind ; therefore the ideas of these ideas will be in God, in so far as he has the knowledge or idea of the human mind, that is (II. xxi.), they will be in the human mind itself, which therefore perceives not only the modifications of the body, but also the ideas of such modifications. Q.E.D.
PROP. XXIII. The mind does not know itself, except in so far as it perceives the ideas of the modifications of the body. Proof.-The idea or knowledge of the mind (II. xx.) follows in God in the same manner, and is referred to God in the same manner, as the idea or knowledge of the body. But since (II. xix.) the human mind does not know the human body itself, that is (II. xi. Coroll.), since the knowledge of the human body is not referred to God, in so far as he constitutes the nature of the human mind ; therefore, neither is the knowledge of the mind referred to God, in so far as he constitutes the essence of the human mind ; therefore (by the same Coroll. II. xi.), the human mind thus far has no knowledge of itself. Further the ideas of the modifications, whereby the body is affected, involve the nature of the human body itself (II. xvi.), that is (II. xiii.), they agree with the nature of the mind ; wherefore the knowledge of these ideas necessarily involves knowledge of the mind ; but (by the last Prop.) the knowledge of these ideas is in the human mind itself ; wherefore the human mind thus far only has knowledge of itself. Q.E.D.
PROP. XXIV. The human mind does not involve an adequate knowledge of the parts composing the human body. Proof.-The parts composing the human body do not belong to the essence of that body, except in so far as they communicate their motions to one another in a certain fixed relation (Def. after Lemma iii.), not in so far as they can be regarded as individuals without relation to the human body. The parts of the human body are highly complex individuals (Post. i.), whose parts (Lemma iv.) can be separated from the human body without in any way destroying the nature and distinctive quality of the latter, and they can communicate their motions (Ax. i., after Lemma iii.) to other bodies in another relation ; therefore (II. iii.) the idea or knowledge of each part will be in God, inasmuch (II. ix.) as he is regarded as affected by another idea of a particular thing, which particular thing is prior in the order of nature to the aforesaid part (II. vii.). We may affirm the same thing of each part of each individual composing the human body ; therefore, the knowledge of each part composing the human body is in God, in so far as he is affected by very many ideas of things, and not in so far as he has the idea of the human body only, in other words, the idea which constitutes the nature of the human mind (II. xiii) ; therefore (II. xi. Coroll.), the human mind does not involve an adequate knowledge of the human body. Q.E.D.
PROP. XXV. The idea of each modification of the human body does not involve an adequate knowledge of the external body. Proof.-We have shown that the idea of a modification of the human body involves the nature of an external body, in so far as that external body conditions the human body in a given manner. But, in so far as the external body is an individual, which has no reference to the human body, the knowledge or idea thereof is in God (II. ix.), in so far as God is regarded as affected by the idea of a further thing, which (II. vii.) is naturally prior to the said external body. Wherefore an adequate knowledge of the external body is not in God, in so far as he has the idea of the modification of the human body ; in other words, the idea of the modification of the human body does not involve an adequate knowledge of the external body. Q.E.D.
PROP. XXVI. The human mind does not perceive any external body as actually existing, except through the ideas of the modifications of its own body.
Proof.-If the human body is in no way affected by a given external body, then (II. vii.) neither is the idea of the human body, in other words, the human mind, affected in any way by the idea of the existence of the said external body, nor does it in any manner perceive its existence. But, in so far as the human body is affected in any way by a given external body, thus far (II. xvi. and Coroll.) it perceives that external body. Q.E.D. Corollary.-In so far as the human mind imagines an external body, it has not an adequate knowledge thereof. Proof.-When the human mind regards external bodies through the ideas of the modifications of its own body, we say that it imagines (see II. xvii. note) ; now the mind can only imagine external bodies as actually existing. Therefore (by II. xxv.), in so far as the mind imagines external bodies, it has not an adequate knowledge of them. Q.E.D.
PROP. XXVII. The idea of each modification of the human body does not involve an adequate knowledge of the human body itself. Proof.-Every idea of a modification of the human body involves the nature of the human body, in so far as the human body is regarded as affected in a given manner (II. xvi.). But, inasmuch as the human body is an individual which may be affected in many other ways, the idea of the said modification, &c. Q.E.D.
PROP. XXVIII. The ideas of the modifications of the human body, in so far as they have reference only to the human mind, are not clear and distinct, but confused.
Proof.-The ideas of the modifications of the human body involve the nature both of the human body and of external bodies (II. xvi.) ; they must involve the nature not only of the human body but also of its parts ; for the modifications are modes (Post. iii.), whereby the parts of the human body, and, consequently, the human body as a whole are affected. But (by II. xxiv., xxv.) the adequate knowledge of external bodies, as also of the parts composing the human body, is not in God, in so far as he is regarded as affected by the human mind, but in so far as he is regarded as affected by other ideas. These ideas of modifications, in so far as they are referred to the human mind alone, are as consequences without premisses, in other words, confused ideas. Q.E.D.
Note.-The idea which constitutes the nature of the human mind is, in the same manner, proved not to be, when considered in itself alone, clear and distinct ; as also is the case with the idea of the human mind, and the ideas of the ideas of the modifications of the human body, in so far as they are referred to the mind only, as everyone may easily see.
PROP. XXIX. The idea of the idea of each modification of the human body does not involve an adequate knowledge of the human mind.
Proof.-The idea of a modification of the human body (II. xxvii.) does not involve an adequate knowledge of the said body, in other words, does not adequately express its nature ; that is (II. xiii.) it does not agree with the nature of the mind adequately ; therefore (I. Ax. vi) the idea of this idea does not adequately express the nature of the human mind, or does not involve an adequate knowledge thereof.
Corollary.-Hence it follows that the human mind, when it perceives things after the common order of nature, has not an adequate but only a confused and fragmentary knowledge of itself, of its own body, and of external bodies. For the mind does not know itself, except in so far as it perceives the ideas of the modifications of body (II. xxiii.). It only perceives its own body (II. xix.) through the ideas of the modifications, and only perceives external bodies through the same means ; thus, in so far as it has such ideas of modification, it has not an adequate knowledge of itself (II. xxix.), nor of its own body (II. xxvii.), nor of external bodies (II. xxv.), but only a fragmentary and confused knowledge thereof (II. xxviii. and note). Q.E.D.
Note.-I say expressly, that the mind has not an adequate but only a confused knowledge of itself, its own body, and of external bodies, whenever it perceives things after the common order of nature ; that is, whenever it is determined from without, namely, by the fortuitous play of circumstance, to regard this or that ; not at such times as it is determined from within, that is, by the fact of regarding several things at once, to understand their points of agreement, difference, and contrast. Whenever it is determined in anywise from within, it regards things clearly and distinctly, as I will show below.
PROP. XXX. We can only have a very inadequate knowledge of the duration of our body.
Proof.-The duration of our body does not depend on its essence (II. Ax. i.), nor on the absolute nature of God (I. xxi.). But (I. xxviii.) it is conditioned to exist and operate by causes, which in their turn are conditioned to exist and operate in a fixed and definite relation by other causes, these last again being conditioned by others, and so on to infinity. The duration of our body therefore depends on the common order of nature, or the constitution of things. Now, however a thing may be constituted, the adequate knowledge of that thing is in God, in so far as he has the ideas of all things, and not in so far as he has the idea of the human body only. (II. ix. Coroll.) Wherefore the knowledge of the duration of our body is in God very inadequate, in so far as he is only regarded as constituting the nature of the human mind ; that is (II. xi. Coroll.), this knowledge is very inadequate to our mind. Q.E.D.
PROP. XXXI. We can only have a very inadequate knowledge of the duration of particular things external to ourselves. Proof.-Every particular thing, like the human body, must be conditioned by another particular thing to exist and operate in a fixed and definite relation ; this other particular thing must likewise be conditioned by a third, and so on to infinity. (I. xxviii.) As we have shown in the foregoing proposition, from this common property of particular things, we have only a very inadequate knowledge of the duration of our body ; we must draw a similar conclusion with regard to the duration of particular things, namely, that we can only have a very inadequate knowledge of the duration thereof. Q.E.D.
Corollary.-Hence it follows that all particular things are contingent and perishable. For we can have no adequate idea of their duration (by the last Prop.), and this is what we must understand by the contingency and perishableness of things. (I. xxxiii., Note i.) For (I. xxix.), except in this sense, nothing is contingent.
PROP. XXXII. All ideas, in so far as they are referred to God, are true.
Proof.-All ideas which are in God agree in every respect with their objects (II. vii. Coroll.), therefore (I. Ax. vi.) they are all true. Q.E.D.
PROP. XXXIII. There is nothing positive in ideas, which causes them to be called false.
Proof.-If this be denied, conceive, if possible, a positive mode of thinking, which should constitute the distinctive quality of falsehood. Such a mode of thinking cannot be in God (II. xxxii.) ; external to God it cannot be or be conceived (I. xv.). Therefore there is nothing positive in ideas which causes them to be called false. Q.E.D.
PROP. XXXIV. Every idea, which in us is absolute or adequate and perfect, is true.
Proof.-When we say that an idea in us is adequate and perfect, we say, in other words (II. xi. Coroll.), that the idea is adequate and perfect in God, in so far as he constitutes the essence of our mind ; consequently (II. xxxii.), we say that such an idea is true. Q.E.D.
PROP. XXXV. Falsity consists in the privation of knowledge, which inadequate, fragmentary, or confused ideas involve. Proof.-There is nothing positive in ideas, which causes them to be called false (II. xxxiii.) ; but falsity cannot consist in simple privation (for minds, not bodies, are said to err and to be mistaken), neither can it consist in absolute ignorance, for ignorance and error are not identical ; wherefore it consists in the privation of knowledge, which inadequate, fragmentary, or confused ideas involve. Q.E.D.
Note.-In the note to II. xvii. I explained how error consists in the privation of knowledge, but in order to throw more light on the subject I will give an example. For instance, men are mistaken in thinking themselves free ; their opinion is made up of consciousness of their own actions, and ignorance of the causes by which they are conditioned. Their idea of freedom, therefore, is simply their ignorance of any cause for their actions. As for their saying that human actions depend on the will, this is a mere phrase without any idea to correspond thereto. What the will is, and how it moves the body, they none of them know ; those who boast of such knowledge, and feign dwellings and habitations for the soul, are wont to provoke either laughter or disgust. So, again, when we look at the sun, we imagine that it is distant from us about two hundred feet ; this error does not lie solely in this fancy, but in the fact that, while we thus imagine, we do not know the sun’s true distance or the cause of the fancy. For although we afterwards learn, that the sun is distant from us more than six hundred of the earth’s diameters, we none the less shall fancy it to be near ; for we do not imagine the sun as near us, because we are ignorant of its true distance, but because the modification of our body involves the essence of the sun, in so far as our said body is affected thereby.
PROP. XXXVI. Inadequate and confused ideas follow by the same necessity, as adequate or clear and distinct ideas. Proof.-All ideas are in God (I. xv.), and in so far as they are referred to God are true (II. xxxii.) and (II. vii. Coroll.) adequate ; therefore there are no ideas confused or inadequate, except in respect to a particular mind (cf. II. xxiv. and xxviii.) ; therefore all ideas, whether adequate or inadequate, follow by the same necessity (II. vi.). Q.E.D.
PROP. XXXVII. That which is common to all (cf. Lemma II., above), and which is equally in a part and in the whole, does not constitute the essence of any particular thing. Proof.-If this be denied, conceive, if possible, that it constitutes the essence of some particular thing ; for instance, the essence of B. Then (II. Def. ii.) it cannot without B either exist or be conceived ; but this is against our hypothesis. Therefore it does not appertain to B’s essence, nor does it constitute the essence of any particular thing. Q.E.D.
PROP. XXXVIII. Those things, which are common to all, and which are equally in a part and in the whole, cannot be conceived except adequately.
Proof.-Let A be something, which is common to all bodies, and which is equally present in the part of any given body and in the whole. I say A cannot be conceived except adequately. For the idea thereof in God will necessarily be adequate (II. vii. Coroll.), both in so far as God has the idea of the human body, and also in so far as he has the idea of the modifications of the human body, which (II. xvi., xxv., xxvii.) involve in part the nature of the human body and the nature of external bodies ; that is (II. xii., xiii.), the idea in God will necessarily be adequate, both in so far as he constitutes the human mind, and in so far as he has the ideas, which are in the human mind. Therefore the mind (II. xi. Coroll.) necessarily perceives A adequately, and has this adequate perception, both in so far as it perceives itself, and in so far as it perceives its own or any external body, nor can A be conceived in any other manner. Q.E.D.
Corollary-Hence it follows that there are certain ideas or notions common to all men ; for (by Lemma ii.) all bodies agree in certain respects, which (by the foregoing Prop.) must be adequately or clearly and distinctly perceived by all.
PROP. XXXIX. That, which is common to and a property of the human body and such other bodies as are wont to affect the human body, and which is present equally in each part of either, or in the whole, will be represented by an adequate idea in the mind. Proof.-If A be that, which is common to and a property of the human body and external bodies, and equally present in the human body and in the said external bodies, in each part of each external body and in the whole, there will be an adequate idea of A in God (II. vii. Coroll.), both in so far as he has the idea of the human body, and in so far as he has the ideas of the given external bodies. Let it now be granted, that the human body is affected by an external body through that, which it has in common therewith, namely, A ; the idea of this modification will involve the property A (II. xvi.), and therefore (II. vii. Coroll.) the idea of this modification, in so far as it involves the property A, will be adequate in God, in so far as God is affected by the idea of the human body ; that is (II. xiii.), in so far as he constitutes the nature of the human mind ; therefore (II. xi. Coroll.) this idea is also adequate in the human mind. Q.E.D. Corollary.-Hence it follows that the mind is fitted to perceive adequately more things, in proportion as its body has more in common with other bodies.
PROP. XL. Whatsoever ideas in the mind follow from ideas which are therein adequate, are also themselves adequate. Proof.-This proposition is self-evident. For when we say that an idea in the human mind follows from ideas which are therein adequate, we say, in other words (II. xi. Coroll.), that an idea is in the divine intellect, whereof God is the cause, not in so far as he is infinite, nor in so far as he is affected by the ideas of very many particular things, but only in so far as he constitutes the essence of the human mind. Note I.-I have thus set forth the cause of those notions, which are common to all men, and which form the basis of our ratiocination. But there are other causes of certain axioms or notions, which it would be to the purpose to set forth by this method of ours ; for it would thus appear what notions are more useful than others, and what notions have scarcely any use at all. Furthermore, we should see what notions are common to all men, and what notions are only clear and distinct to those who are unshackled by prejudice, and we should detect those which are ill-founded. Again we should discern whence the notions called secondary derived their origin, and consequently the axioms on which they are founded, and other points of interest connected with these questions. But I have decided to pass over the subject here, partly because I have set it aside for another treatise, partly because I am afraid of wearying the reader by too great prolixity. Nevertheless, in order not to omit anything necessary to be known, I will briefly set down the causes, whence are derived the terms styled transcendental, such as Being, Thing, Something. These terms arose from the fact, that the human body, being limited, is only capable of distinctly forming a certain number of images (what an image is I explained in the II. xvii. note) within itself at the same time ; if this number be exceeded, the images will begin to be confused ; if this number of images, of which the body is capable of forming distinctly within itself, be largely exceeded, all will become entirely confused one with another. This being so, it is evident (from II. Prop. xvii. Coroll., and xviii.) that the human mind can distinctly imagine as many things simultaneously, as its body can form images simultaneously. When the images become quite confused in the body, the mind also imagines all bodies confusedly without any distinction, and will comprehend them, as it were, under one attribute, namely, under the attribute of Being, Thing, &c. The same conclusion can be drawn from the fact that images are not always equally vivid, and from other analogous causes, which there is no need to explain here ; for the purpose which we have in view it is sufficient for us to consider one only. All may be reduced to this, that these terms represent ideas in the highest degree confused. From similar causes arise those notions, which we call general, such as man, horse, dog, &c. They arise, to wit, from the fact that so many images, for instance, of men, are formed simultaneously in the human mind, that the powers of imagination break down, not indeed utterly, but to the extent of the mind losing count of small differences between individuals (e.g. colour, size, &c.) and their definite number, and only distinctly imagining that, in which all the individuals, in so far as the body is affected by them, agree ; for that is the point, in which each of the said individuals chiefly affected the body ; this the mind expresses by the name man, and this it predicates of an infinite number of particular individuals. For, as we have said, it is unable to imagine the definite number of individuals. We must, however, bear in mind, that these general notions are not formed by all men in the same way, but vary in each individual according as the point varies, whereby the body has been most often affected and which the mind most easily imagines or remembers. For instance, those who have most often regarded with admiration the stature of man, will by the name of man understand an animal of erect stature ; those who have been accustomed to regard some other attribute, will form a different general image of man, for instance, that man is a laughing animal, a two-footed animal without feathers, a rational animal, and thus, in other cases, everyone will form general images of things according to the habit of his body.
It is thus not to be wondered at, that among philosophers, who seek to explain things in nature merely by the images formed of them, so many controversies should have arisen. Note II.-From all that has been said above it is clear, that we, in many cases, perceive and form our general notions :-(1.) From particular things represented to our intellect fragmentarily, confusedly, and without order through our senses (II. xxix. Coroll.) ; I have settled to call such perceptions by the name of knowledge from the mere suggestions of experience.4 (2.) From symbols, e.g., from the fact of having read or heard certain words we remember things and form certain ideas concerning them, similar to those through which we imagine things (II. xviii. note). I shall call both these ways of regarding things knowledge of the first kind, opinion, or imagination. (3.) From the fact that we have notions common to all men, and adequate ideas of the properties of things (II. xxxviii. Coroll., xxxix. and Coroll. and xl.) ; this I call reason and knowledge of the second kind. Besides these two kinds of knowledge, there is, as I will hereafter show, a third kind of knowledge, which we will call intuition. This kind of knowledge proceeds from an adequate idea of the absolute essence of certain attributes of God to the adequate knowledge of the essence of things. I will illustrate all three kinds of knowledge by a single example. Three numbers are given for finding a fourth, which shall be to the third as the second is to the first. Tradesmen without hesitation multiply the second by the third, and divide the product by the first ; either because they have not forgotten the rule which they received from a master without any proof, or because they have often made trial of it with simple numbers, or by virtue of the proof of the nineteenth proposition of the seventh book of Euclid, namely, in virtue of the general property of proportionals.
But with very simple numbers there is no need of this. For instance, one, two, three, being given, everyone can see that the fourth proportional is six ; and this is much clearer, because we infer the fourth number from an intuitive grasping of the ratio, which the first bears to the second.
PROP. XLI. Knowledge of the first kind is the only source of falsity, knowledge of the second and third kinds is necessarily true.
Proof.-To knowledge of the first kind we have (in the foregoing note) assigned all those ideas, which are inadequate and confused ; therefore this kind of knowledge is the only source of falsity (II. xxxv.). Furthermore, we assigned to the second and third kinds of knowledge those ideas which are adequate ; therefore these kinds are necessarily true (II. xxxiv.). Q.E.D.
PROP. XLII. Knowledge of the second and third kinds, not knowledge of the first kind, teaches us to distinguish the true from the false.
Proof.-This proposition is self-evident. He, who knows how to distinguish between true and false, must have an adequate idea of true and false. That is (II. xl., note ii.), he must know the true and the false by the second or third kind of knowledge.
PROP. XLIII. He, who has a true idea, simultaneously knows that he has a true idea, and cannot doubt of the truth of the thing perceived.
Proof.-A true idea in us is an idea which is adequate in God, in so far as he is displayed through the nature of the human mind (II. xi. Coroll.). Let us suppose that there is in God, in so far as he is displayed through the human mind, an adequate idea, A. The idea of this idea must also necessarily be in God, and be referred to him in the same way as the idea A (by II. xx., whereof the proof is of universal application). But the idea A is supposed to be referred to God, in so far as he is displayed through the human mind ; therefore, the idea of the idea A must be referred to God in the same manner ; that is (by II. xi. Coroll.), the adequate idea of the idea A will be in the mind, which has the adequate idea A ; therefore he, who has an adequate idea or knows a thing truly (II. xxxiv.), must at the same time have an adequate idea or true knowledge of his knowledge ; that is, obviously, he must be assured. Q.E.D. Note.-I explained in the note to II. xxi. what is meant by the idea of an idea ; but we may remark that the foregoing proposition is in itself sufficiently plain. No one, who has a true idea, is ignorant that a true idea involves the highest certainty. For to have a true idea is only another expression for knowing a thing perfectly, or as well as possible. No one, indeed, can doubt of this, unless he thinks that an idea is something lifeless, like a picture on a panel, and not a mode of thinking-namely, the very act of understanding. And who, I ask, can know that he understands anything, unless he do first understand it? In other words, who can know that he is sure of a thing, unless he be first sure of that thing? Further, what can there be more clear, and more certain, than a true idea as a standard of truth? Even as light displays both itself and darkness, so is truth a standard both of itself and of falsity. I think I have thus sufficiently answered these questions-namely, if a true idea is distinguished from a false idea, only in so far as it is said to agree with its object, a true idea has no more reality or perfection than a false idea (since the two are only distinguished by an extrinsic mark) ; consequently, neither will a man who has a true idea have any advantage over him who has only false ideas. Further, how comes it that men have false ideas? Lastly, how can anyone be sure, that he has ideas which agree with their objects? These questions, I repeat, I have, in my opinion, sufficiently answered. The difference between a true idea and a false idea is plain : from what was said in II. xxxv., the former is related to the latter as being is to not-being. The causes of falsity I have set forth very clearly in II. xix. and II. xxxv. with the note. From what is there stated, the difference between a man who has true ideas, and a man who has only false ideas, is made apparent. As for the last question-as to how a man can be sure that he has ideas that agree with their objects, I have just pointed out, with abundant clearness, that his knowledge arises from the simple fact, that he has an idea which corresponds with its object-in other words, that truth is its own standard. We may add that our mind, in so far as it perceives things truly, is part of the infinite intellect of God (II. xi. Coroll.) ; therefore, the clear and distinct ideas of the mind are as necessarily true as the ideas of God.
PROP. XLIV. It is not in the nature of reason to regard things as contingent, but as necessary.
Proof.-It is in the nature of reason to perceive things truly (II. xli.), namely (I. Ax. vi.), as they are in themselves-that is (I. xxix.), not as contingent, but as necessary. Q.E.D. Corollary I.-Hence it follows, that it is only through our imagination that we consider things, whether in respect to the future or the past, as contingent.
Note.-How this way of looking at things arises, I will briefly explain. We have shown above (II. xvii. and Coroll.) that the mind always regards things as present to itself, even though they be not in existence, until some causes arise which exclude their existence and presence. Further (II. xviii.), we showed that, if the human body has once been affected by two external bodies simultaneously, the mind, when it afterwards imagines one of the said external bodies, will straightway remember the other-that is, it will regard both as present to itself, unless there arise causes which exclude their existence and presence. Further, no one doubts that we imagine time, from the fact that we imagine bodies to be moved some more slowly than others, some more quickly, some at equal speed. Thus, let us suppose that a child yesterday saw Peter for the first time in the morning, Paul at noon, and Simon in the evening ; then, that today he again sees Peter in the morning. It is evident, from II. Prop. xviii., that, as soon as he sees the morning light, he will imagine that the sun will traverse the same parts of the sky, as it did when he saw it on the preceding day ; in other words, he will imagine a complete day, and, together with his imagination of the morning, he will imagine Peter ; with noon, he will imagine Paul ; and with evening, he will imagine Simon-that is, he will imagine the existence of Paul and Simon in relation to a future time ; on the other hand, if he sees Simon in the evening, he will refer Peter and Paul to a past time, by imagining them simultaneously with the imagination of a past time. If it should at any time happen, that on some other evening the child should see James instead of Simon, he will, on the following morning, associate with his imagination of evening sometimes Simon, sometimes James, not both together : for the child is supposed to have seen, at evening, one or other of them, not both together. His imagination will therefore waver ; and, with the imagination of future evenings, he will associate first one, then the other-that is, he will imagine them in the future, neither of them as certain, but both as contingent. This wavering of the imagination will be the same, if the imagination be concerned with things which we thus contemplate, standing in relation to time past or time present : consequently, we may imagine things as contingent, whether they be referred to time present, past, or future.
Corollary II.-It is in the nature of reason to perceive things under a certain form of eternity (sub quâdam æternitatis specie).
Proof.-It is in the nature of reason to regard things, not as contingent, but as necessary (II. xliv.). Reason perceives this necessity of things (II. xli.) truly-that is (I. Ax. vi.), as it is in itself. But (I. xvi.) this necessity of things is the very necessity of the eternal nature of God ; therefore, it is in the nature of reason to regard things under this form of eternity. We may add that the bases of reason are the notions (II. xxxviii.), which answer to things common to all, and which (II. xxxvii.) do not answer to the essence of any particular thing : which must therefore be conceived without any relation to time, under a certain form of eternity.
PROP. XLV. Every idea of every body, or of every particular thing actually existing, necessarily involves the eternal and infinite essence of God.
Proof.-The idea of a particular thing actually existing necessarily involves both the existence and the essence of the said thing (II. viii.). Now particular things cannot be conceived without God (I. xv.) ; but, inasmuch as (II. vi.) they have God for their cause, in so far as he is regarded under the attribute of which the things in question are modes, their ideas must necessarily involve (I. Ax. iv.) the conception of the attributes of those ideas-that is (I. vi.), the eternal and infinite essence of God. Q.E.D.
Note.-By existence I do not here mean duration-that is, existence in so far as it is conceived abstractedly, and as a certain form of quantity. I am speaking of the very nature of existence, which is assigned to particular things, because they follow in infinite numbers and in infinite ways from the eternal necessity of God’s nature (I. xvi.). I am speaking, I repeat, of the very existence of particular things, in so far as they are in God. For although each particular thing be conditioned by another particular thing to exist in a given way, yet the force whereby each particular thing perseveres in existing follows from the eternal necessity of God’s nature (cf. I. xxiv. Coroll.).
PROP. XLVI. The knowledge of the eternal and infinite essence of God which every idea involves is adequate and perfect. Proof.-The proof of the last proposition is universal ; and whether a thing be considered as a part or a whole, the idea thereof, whether of the whole or of a part (by the last Prop.), will involve God’s eternal and infinite essence. Wherefore, that, which gives knowledge of the eternal and infinite essence of God, is common to all, and is equally in the part and in the whole ; therefore (II. xxxviii.) this knowledge will be adequate. Q.E.D.
PROP. XLVII. The human mind has an adequate knowledge of the eternal and infinite essence of God.
Proof.-The human mind has ideas (II. xxii.), from which (II. xxiii.) it perceives itself and its own body (II. xix.) and external bodies (II. xvi. Coroll. i. and II. xvii.) as actually existing ; therefore (II. xlv. and xlvi.) it has an adequate knowledge of the eternal and infinite essence of God. Q.E.D. Note.-Hence we see, that the infinite essence and the eternity of God are known to all. Now as all things are in God, and are conceived through God, we can from this knowledge infer many things, which we may adequately know, and we may form that third kind of knowledge of which we spoke in the note to II. xl., and of the excellence and use of which we shall have occasion to speak in Part V. Men have not so clear a knowledge of God as they have of general notions, because they are unable to imagine God as they do bodies, and also because they have associated the name God with images of things that they are in the habit of seeing, as indeed they can hardly avoid doing, being, as they are, men, and continually affected by external bodies. Many errors, in truth, can be traced to this head, namely, that we do not apply names to things rightly. For instance, when a man says that the lines drawn from the centre of a circle to its circumference are not equal, he then, at all events, assuredly attaches a meaning to the word circle different from that assigned by mathematicians. So again, when men make mistakes in calculation, they have one set of figures in their mind, and another on the paper. If we could see into their minds, they do not make a mistake ; they seem to do so, because we think, that they have the same numbers in their mind as they have on the paper. If this were not so, we should not believe them to be in error, any more than I thought that a man was in error, whom I lately heard exclaiming that his entrance hall had flown into a neighbour’s hen, for his meaning seemed to me sufficiently clear. Very many controversies have arisen from the fact, that men do not rightly explain their meaning, or do not rightly interpret the meaning of others. For, as a matter of fact, as they flatly contradict themselves, they assume now one side, now another, of the argument, so as to oppose the opinions, which they consider mistaken and absurd in their opponents.
PROP. XLVIII. In the mind there is no absolute or free will ; but the mind is determined to wish this or that by a cause, which has also been determined by another cause, and this last by another cause, and so on to infinity.
Proof.-The mind is a fixed and definite mode of thought (II. xi.), therefore it cannot be the free cause of its actions (I. xvii. Coroll. ii.) ; in other words, it cannot have an absolute faculty of positive or negative volition ; but (by I. xxviii.) it must be determined by a cause, which has also been determined by another cause, and this last by another, &c. Q.E.D. Note.-In the same way it is proved, that there is in the mind no absolute faculty of understanding, desiring, loving, &c. Whence it follows, that these and similar faculties are either entirely fictitious, or are merely abstract and general terms, such as we are accustomed to put together from particular things. Thus the intellect and the will stand in the same relation to this or that idea, or this or that volition, as “lapidity” to this or that stone, or as “man” to Peter and Paul. The cause which leads men to consider themselves free has been set forth in the Appendix to Part I. But, before I proceed further, I would here remark that, by the will to affirm and decide, I mean the faculty, not the desire. I mean, I repeat, the faculty, whereby the mind affirms or denies what is true or false, not the desire, wherewith the mind wishes for or turns away from any given thing. After we have proved, that these faculties of ours are general notions, which cannot be distinguished from the particular instances on which they are based, we must inquire whether volitions themselves are anything besides the ideas of things. We must inquire, I say, whether there is in the mind any affirmation or negation beyond that, which the idea, in so far as it is an idea, involves. On which subject see the following proposition, and II. Def. iii., lest the idea of pictures should suggest itself. For by ideas I do not mean images such as are formed at the back of the eye, or in the midst of the brain, but the conceptions of thought.
PROP. XLIX. There is in the mind no volition or affirmation and negation, save that which an idea, inasmuch as it is an idea, involves.
Proof.-There is in the mind no absolute faculty of positive or negative volition, but only particular volitions, namely, this or that affirmation, and this or that negation. Now let us conceive a particular volition, namely, the mode of thinking whereby the mind affirms, that the three interior angles of a triangle are equal to two right angles. This affirmation involves the conception or idea of a triangle, that is, without the idea of a triangle it cannot be conceived. It is the same thing to say, that the concept A must involve the concept B, as it is to say, that A cannot be conceived without B. Further, this affirmation cannot be made (II. Ax. iii.) without the idea of a triangle. Therefore, this affirmation can neither be nor be conceived, without the idea of a triangle. Again, this idea of a triangle must involve this same affirmation, namely, that its three interior angles are equal to two right angles. Wherefore, and vice versâ, this idea of a triangle can neither be nor be conceived without this affirmation, therefore, this affirmation belongs to the essence of the idea of a triangle, and is nothing besides. What we have said of this volition (inasmuch as we have selected it at random) may be said of any other volition, namely, that it is nothing but an idea. Q.E.D.
Corollary.-Will and understanding are one and the same. Proof.-Will and understanding are nothing beyond the individual volitions and ideas (II. xlviii. and note). But a particular volition and a particular idea are one and the same (by the foregoing Prop.) ; therefore, will and understanding are one and the same. Q.E.D.
Note.-We have thus removed the cause which is commonly assigned for error. For we have shown above, that falsity consists solely in the privation of knowledge involved in ideas which are fragmentary and confused. Wherefore, a false idea, inasmuch as it is false, does not involve certainty. When we say, then, that a man acquiesces in what is false, and that he has no doubts on the subject, we do not say that he is certain, but only that he does not doubt, or that he acquiesces in what is false, inasmuch as there are no reasons, which should cause his imagination to waver (see II. xliv. note). Thus, although the man be assumed to acquiesce in what is false, we shall never say that he is certain. For by certainty we mean something positive (II. xliii. and note), not merely the absence of doubt. However, in order that the foregoing proposition may be fully explained, I will draw attention to a few additional points, and I will furthermore answer the objections which may be advanced against our doctrine. Lastly, in order to remove every scruple, I have thought it worth while to point out some of the advantages, which follow therefrom. I say “some,” for they will be better appreciated from what we shall set forth in the fifth part.
I begin, then, with the first point, and warn my readers to make an accurate distinction between an idea, or conception of the mind, and the images of things which we imagine. It is further necessary that they should distinguish between idea and words, whereby we signify things. These three-namely, images, words, and ideas-are by many persons either entirely confused together, or not distinguished with sufficient accuracy or care, and hence people are generally in ignorance, how absolutely necessary is a knowledge of this doctrine of the will, both for philosophic purposes and for the wise ordering of life. Those who think that ideas consist in images which are formed in us by contact with external bodies, persuade themselves that the ideas of those things, whereof we can form no mental picture, are not ideas, but only figments, which we invent by the free decree of our will ; they thus regard ideas as though they were inanimate pictures on a panel, and, filled with this misconception, do not see that an idea, inasmuch as it is an idea, involves an affirmation or negation. Again, those who confuse words with ideas, or with the affirmation which an idea involves, think that they can wish something contrary to what they feel, affirm, or deny. This misconception will easily be laid aside by one, who reflects on the nature of knowledge, and seeing that it in no wise involves the conception of extension, will therefore clearly understand, that an idea (being a mode of thinking) does not consist in the image of anything, nor in words. The essence of words and images is put together by bodily motions, which in no wise involve the conception of thought.
These few words on this subject will suffice : I will therefore pass on to consider the objections, which may be raised against our doctrine. Of these, the first is advanced by those, who think that the will has a wider scope than the understanding, and that therefore it is different therefrom. The reason for their holding the belief, that the will has wider scope than the understanding, is that they assert, that they have no need of an increase in their faculty of assent, that is of affirmation or negation, in order to assent to an infinity of things which we do not perceive, but that they have need of an increase in their faculty of understanding. The will is thus distinguished from the intellect, the latter being finite and the former infinite. Secondly, it may be objected that experience seems to teach us especially clearly, that we are able to suspend our judgment before assenting to things which we perceive ; this is confirmed by the fact that no one is said to be deceived, in so far as he perceives anything, but only in so far as he assents or dissents. For instance, he who feigns a winged horse, does not therefore admit that a winged horse exists ; that is, he is not deceived, unless he admits in addition that a winged horse does exist. Nothing therefore seems to be taught more clearly by experience, than that the will or faculty of assent is free and different from the faculty of understanding. Thirdly, it may be objected that one affirmation does not apparently contain more reality than another ; in other words, that we do not seem to need for affirming, that what is true is true, any greater power than for affirming, that what is false is true. We have, however, seen that one idea has more reality or perfection than another, for as objects are some more excellent than others, so also are the ideas of them some more excellent than others ; this also seems to point to a difference between the understanding and the will. Fourthly, it may be objected, if man does not act from free will, what will happen if the incentives to action are equally balanced, as in the case of Buridan’s ass? Will he perish of hunger and thirst? If I say that he would, I shall seem to have in my thoughts an ass or the statue of a man rather than an actual man. If I say that he would not, he would then determine his own action, and would consequently possess the faculty of going and doing whatever he liked. Other objections might also be raised, but, as I am not bound to put in evidence everything that anyone may dream, I will only set myself to the task of refuting those I have mentioned, and that as briefly as possible.
To the first objection I answer, that I admit that the will has a wider scope than the understanding, if by the understanding be meant only clear and distinct ideas ; but I deny that the will has a wider scope than the perceptions, and the faculty of forming conceptions ; nor do I see why the faculty of volition should be called infinite, any more than the faculty of feeling : for, as we are able by the same faculty of volition to affirm an infinite number of things (one after the other, for we cannot affirm an infinite number simultaneously), so also can we, by the same faculty of feeling, feel or perceive (in succession) an infinite number of bodies. If it be said that there is an infinite number of things which we cannot perceive, I answer, that we cannot attain to such things by any thinking, nor, consequently, by any faculty of volition. But, it may still be urged, if God wished to bring it about that we should perceive them, he would be obliged to endow us with a greater faculty of perception, but not a greater faculty of volition than we have already. This is the same as to say that, if God wished to bring it about that we should understand an infinite number of other entities, it would be necessary for him to give us a greater understanding, but not a more universal idea of entity than that which we have already, in order to grasp such infinite entities. We have shown that will is a universal entity or idea, whereby we explain all particular volitions-in other words, that which is common to all such volitions.
As, then, our opponents maintain that this idea, common or universal to all volitions, is a faculty, it is little to be wondered at that they assert, that such a faculty extends itself into the infinite, beyond the limits of the understanding : for what is universal is predicated alike of one, of many, and of an infinite number of individuals.
To the second objection I reply by denying, that we have a free power of suspending our judgment : for, when we say that anyone suspends his judgment, we merely mean that he sees, that he does not perceive the matter in question adequately. Suspension of judgment is, therefore, strictly speaking, a perception, and not free will. In order to illustrate the point, let us suppose a boy imagining a horse, and perceive nothing else. Inasmuch as this imagination involves the existence of the horse (II. xvii. Coroll.), and the boy does not perceive anything which would exclude the existence of the horse, he will necessarily regard the horse as present : he will not be able to doubt of its existence, although he be not certain thereof. We have daily experience of such a state of things in dreams ; and I do not suppose that there is anyone, who would maintain that, while he is dreaming, he has the free power of suspending his judgment concerning the things in his dream, and bringing it about that he should not dream those things, which he dreams that he sees ; yet it happens, notwithstanding, that even in dreams we suspend our judgment, namely, when we dream that we are dreaming. Further, I grant that no one can be deceived, so far as actual perception extends-that is, I grant that the mind’s imaginations, regarded in themselves, do not involve error (II. xvii. note) ; but I deny, that a man does not, in the act of perception, make any affirmation. For what is the perception of a winged horse, save affirming that a horse has wings? If the mind could perceive nothing else but the winged horse, it would regard the same as present to itself : it would have no reasons for doubting its existence, nor any faculty of dissent, unless the imagination of a winged horse be joined to an idea which precludes the existence of the said horse, or unless the mind perceives that the idea which it possess of a winged horse is inadequate, in which case it will either necessarily deny the existence of such a horse, or will necessarily be in doubt on the subject.
I think that I have anticipated my answer to the third objection, namely, that the will is something universal which is predicated of all ideas, and that it only signifies that which is common to all ideas, namely, an affirmation, whose adequate essence must, therefore, in so far as it is thus conceived in the abstract, be in every idea, and be, in this respect alone, the same in all, not in so far as it is considered as constituting the idea’s essence : for, in this respect, particular affirmations differ one from the other, as much as do ideas. For instance, the affirmation which involves the idea of a circle, differs from that which involves the idea of a triangle, as much as the idea of a circle differs from the idea of a triangle. Further, I absolutely deny, that we are in need of an equal power of thinking, to affirm that that which is true is true, and to affirm that that which is false is true. These two affirmations, if we regard the mind, are in the same relation to one another as being and not-being ; for there is nothing positive in ideas, which constitutes the actual reality of falsehood (II. xxxv. note, and xlvii. note). We must therefore conclude, that we are easily deceived, when we confuse universals with singulars, and the entities of reason and abstractions with realities. As for the fourth objection, I am quite ready to admit, that a man placed in the equilibrium described (namely, as perceiving nothing but hunger and thirst, a certain food and a certain drink, each equally distant from him) would die of hunger and thirst. If I am asked, whether such an one should not rather be considered an ass than a man ; I answer, that I do not know, neither do I know how a man should be considered, who hangs himself, or how we should consider children, fools, madmen, &c.
It remains to point out the advantages of a knowledge of this doctrine as bearing on conduct, and this may be easily gathered from what has been said. The doctrine is good, 1. Inasmuch as it teaches us to act solely according to the decree of God, and to be partakers in the Divine nature, and so much the more, as we perform more perfect actions and more and more understand God. Such a doctrine not only completely tranquilizes our spirit, but also shows us where our highest happiness or blessedness is, namely, solely in the knowledge of God, whereby we are led to act only as love and piety shall bid us. We may thus clearly understand, how far astray from a true estimate of virtue are those who expect to be decorated by God with high rewards for their virtue, and their best actions, as for having endured the direst slavery ; as if virtue and the service of God were not in itself happiness and perfect freedom. 2. Inasmuch as it teaches us, how we ought to conduct ourselves with respect to the gifts of fortune, or matters which are not in our power, and do not follow from our nature. For it shows us, that we should await and endure fortune’s smiles or frowns with an equal mind, seeing that all things follow from the eternal decree of God by the same necessity, as it follows from the essence of a triangle, that the three angles are equal to two right angles.
3. This doctrine raises social life, inasmuch as it teaches us to hate no man, neither to despise, to deride, to envy, or to be angry with any. Further, as it tells us that each should be content with his own, and helpful to his neighbour, not from any womanish pity, favour, or superstition, but solely by the guidance of reason, according as the time and occasion demand, as I will show in Part III.
4. Lastly, this doctrine confers no small advantage on the commonwealth ; for it teaches how citizens should be governed and led, not so as to become slaves, but so that they may freely do whatsoever things are best.
I have thus fulfilled the promise made at the beginning of this note, and I thus bring the second part of my treatise to a close. I think I have therein explained the nature and properties of the human mind at sufficient length, and, considering the difficulty of the subject, with sufficient clearness. I have laid a foundation, whereon may be raised many excellent conclusions of the highest utility and most necessary to be known, as will, in what follows, be partly made plain.
PART III.
ON THE ORIGIN AND NATURE OF THE EMOTIONS
Most writers on the emotions and on human conduct seem to be treating rather of matters outside nature than of natural phenomena following nature’s general laws. They appear to conceive man to be situated in nature as a kingdom within a kingdom : for they believe that he disturbs rather than follows nature’s order, that he has absolute control over his actions, and that he is determined solely by himself. They attribute human infirmities and fickleness, not to the power of nature in general, but to some mysterious flaw in the nature of man, which accordingly they bemoan, deride, despise, or, as usually happens, abuse : he, who succeeds in hitting off the weakness of the human mind more eloquently or more acutely than his fellows, is looked upon as a seer. Still there has been no lack of very excellent men (to whose toil and industry I confess myself much indebted), who have written many noteworthy things concerning the right way of life, and have given much sage advice to mankind. But no one, so far as I know, has defined the nature and strength of the emotions, and the power of the mind against them for their restraint.
I do not forget, that the illustrious Descartes, though he believed, that the mind has absolute power over its actions, strove to explain human emotions by their primary causes, and, at the same time, to point out a way, by which the mind might attain to absolute dominion over them. However, in my opinion, he accomplishes nothing beyond a display of the acuteness of his own great intellect, as I will show in the proper place. For the present I wish to revert to those, who would rather abuse or deride human emotions than understand them. Such persons will, doubtless think it strange that I should attempt to treat of human vice and folly geometrically, and should wish to set forth with rigid reasoning those matters which they cry out against as repugnant to reason, frivolous, absurd, and dreadful. However, such is my plan. Nothing comes to pass in nature, which can be set down to a flaw therein ; for nature is always the same, and everywhere one and the same in her efficacy and power of action ; that is, nature’s laws and ordinances, whereby all things come to pass and change from one form to another, are everywhere and always the same ; so that there should be one and the same method of understanding the nature of all things whatsoever, namely, through nature’s universal laws and rules. Thus the passions of hatred, anger, envy, and so on, considered in themselves, follow from this same necessity and efficacy of nature ; they answer to certain definite causes, through which they are understood, and possess certain properties as worthy of being known as the properties of anything else, whereof the contemplation in itself affords us delight. I shall, therefore, treat of the nature and strength of the emotions according to the same method, as I employed heretofore in my investigations concerning God and the mind. I shall consider human actions and desires in exactly the same manner, as though I were concerned with lines, planes, and solids.
DEFINITIONS
I. By an adequate cause, I mean a cause through which its effect can be clearly and distinctly perceived. By an inadequate or partial cause, I mean a cause through which, by itself, its effect cannot be understood.
II. I say that we act when anything takes place, either within us or externally to us, whereof we are the adequate cause ; that is (by the foregoing definition) when through our nature something takes place within us or externally to us, which can through our nature alone be clearly and distinctly understood. On the other hand, I say that we are passive as regards something when that something takes place within us, or follows from our nature externally, we being only the partial cause.
III. By emotion I mean the modifications of the body, whereby the active power of the said body is increased or diminished, aided or constrained, and also the ideas of such modifications.
N.B. If we can be the adequate cause of any of these modifications, I then call the emotion an activity, otherwise I call it a passion, or state wherein the mind is passive.
POSTULATES
I. The human body can be affected in many ways, whereby its power of activity is increased or diminished, and also in other ways which do not render its power of activity either greater or less.
N.B. This postulate or axiom rests on Postulate i. and Lemmas v. and vii., which see after II. xiii.
II. The human body can undergo many changes, and, nevertheless, retain the impressions or traces of objects (cf. II. Post. v.), and, consequently, the same images of things (see note II. xvii.).
PROP. I. Our mind is in certain cases active, and in certain cases passive. In so far as it has adequate ideas it is necessarily active, and in so far as it has inadequate ideas, it is necessarily passive.
Proof.-In every human mind there are some adequate ideas, and some ideas that are fragmentary and confused (II. xl. note). Those ideas which are adequate in the mind are adequate also in God, inasmuch as he constitutes the essence of the mind (II. xl. Coroll.), and those which are inadequate in the mind are likewise (by the same Coroll.) adequate in God, not inasmuch as he contains in himself the essence of the given mind alone, but as he, at the same time, contains the minds of other things. Again, from any given idea some effect must necessarily follow (I. 36) ; of this effect God is the adequate cause (III. Def. i.), not inasmuch as he is infinite, but inasmuch as he is conceived as affected by the given idea (II. ix.). But of that effect whereof God is the cause, inasmuch as he is affected by an idea which is adequate in a given mind, of that effect, I repeat, the mind in question is the adequate cause (II. xi. Coroll.). Therefore our mind, in so far as it has adequate ideas (III. Def. ii.), is in certain cases necessarily active ; this was our first point. Again, whatsoever necessarily follows from the idea which is adequate in God, not by virtue of his possessing in himself the mind of one man only, but by virtue of his containing, together with the mind of that one man, the minds of other things also, of such an effect (II. xi. Coroll.) the mind of the given man is not an adequate, but only a partial cause ; thus (III. Def. ii.) the mind, inasmuch as it has inadequate ideas, is in certain cases necessarily passive ; this was our second point. Therefore our mind, &c. Q.E.D.
Corollary.-Hence it follows that the mind is more or less liable to be acted upon, in proportion as it possesses inadequate ideas, and, contrariwise, is more or less active in proportion as it possesses adequate ideas.
PROP. II. Body cannot determine mind to think, neither can mind determine body to motion or rest or any state different from these, if such there be.
Proof.-All modes of thinking have for their cause God, by virtue of his being a thinking thing, and not by virtue of his being displayed under any other attribute (II. vi.). That, therefore, which determines the mind to thought is a mode of thought, and not a mode of extension ; that is (II. Def. i.), it is not body. This was our first point. Again, the motion and rest of a body must arise from another body, which has also been determined to a state of motion or rest by a third body, and absolutely everything which takes place in a body must spring from God, in so far as he is regarded as affected by some mode of extension, and not by some mode of thought (II. vi.) ; that is, it cannot spring from the mind, which is a mode of thought. This was our second point. Therefore body cannot determine mind, &c. Q.E.D.
Note.-This is made more clear by what was said in the note to II. vii., namely, that mind and body are one and the same thing, conceived first under the attribute of thought, secondly, under the attribute of extension. Thus it follows that the order or concatenation of things is identical, whether nature be conceived under the one attribute or the other ; consequently the order of states of activity and passivity in our body is simultaneous in nature with the order of states of activity and passivity in the mind. The same conclusion is evident from the manner in which we proved II. xii.
Nevertheless, though such is the case, and though there be no further room for doubt, I can scarcely believe, until the fact is proved by experience, that men can be induced to consider the question calmly and fairly, so firmly are they convinced that it is merely at the bidding of the mind, that the body is set in motion or at rest, or performs a variety of actions depending solely on the mind’s will or the exercise of thought. However, no one has hitherto laid down the limits to the powers of the body, that is, no one has as yet been taught by experience what the body can accomplish solely by the laws of nature, in so far as she is regarded as extension. No one hitherto has gained such an accurate knowledge of the bodily mechanism, that he can explain all its functions ; nor need I call attention to the fact that many actions are observed in the lower animals, which far transcend human sagacity, and that somnambulists do many things in their sleep, which they would not venture to do when awake : these instances are enough to show, that the body can by the sole laws of its nature do many things which the mind wonders at. Again, no one knows how or by what means the mind moves the body, nor how many various degrees of motion it can impart to the body, nor how quickly it can move it. Thus, when men say that this or that physical action has its origin in the mind, which latter has dominion over the body, they are using words without meaning, or are confessing in specious phraseology that they are ignorant of the cause of the said action, and do not wonder at it.
But, they will say, whether we know or do not know the means whereby the mind acts on the body, we have, at any rate, experience of the fact that unless the human mind is in a fit state to think, the body remains inert. Moreover, we have experience, that the mind alone can determine whether we speak or are silent, and a variety of similar states which, accordingly, we say depend on the mind’s decree. But, as to the first point, I ask such objectors, whether experience does not also teach, that if the body be inactive the mind is simultaneously unfitted for thinking? For when the body is at rest in sleep, the mind simultaneously is in a state of torpor also, and has no power of thinking, such as it possesses when the body is awake. Again, I think everyone’s experience will confirm the statement, that the mind is not at all times equally fit for thinking on a given subject, but according as the body is more or less fitted for being stimulated by the image of this or that object, so also is the mind more or less fitted for contemplating the said object. But, it will be urged, it is impossible that solely from the laws of nature considered as extended substance, we should be able to deduce the causes of buildings, pictures, and things of that kind, which are produced only by human art ; nor would the human body, unless it were determined and led by the mind, be capable of building a single temple. However, I have just pointed out that the objectors cannot fix the limits of the body’s power, or say what can be concluded from a consideration of its sole nature, whereas they have experience of many things being accomplished solely by the laws of nature, which they would never have believed possible except under the direction of mind : such are the actions performed by somnambulists while asleep, and wondered at by their performers when awake. I would further call attention to the mechanism of the human body, which far surpasses in complexity all that has been put together by human art, not to repeat what I have already shown, namely, that from nature, under whatever attribute she be considered, infinite results follow. As for the second objection, I submit that the world would be much happier, if men were as fully able to keep silence as they are to speak. Experience abundantly shows that men can govern anything more easily than their tongues, and restrain anything more easily than their appetites ; when it comes about that many believe, that we are only free in respect to objects which we moderately desire, because our desire for such can easily be controlled by the thought of something else frequently remembered, but that we are by no means free in respect to what we seek with violent emotion, for our desire cannot then be allayed with the remembrance of anything else. However, unless such persons had proved by experience that we do many things which we afterwards repent of, and again that we often, when assailed by contrary emotions, see the better and follow the worse, there would be nothing to prevent their believing that we are free in all things. Thus an infant believes that of its own free will it desires milk, an angry child believes that it freely desires vengeance, a timid child believes that it freely desires to run away ; further, a drunken man believes that he utters from the free decision of his mind words which, when he is sober, he would willingly have withheld : thus, too, a delirious man, a garrulous woman, a child, and others of like complexion, believe that they speak from the free decision of their mind, when they are in reality unable to restrain their impulse to talk. Experience teaches us no less clearly than reason, that men believe themselves to be free, simply because they are conscious of their actions, and unconscious of the causes whereby those actions are determined ; and, further, it is plain that the dictates of the mind are but another name for the appetites, and therefore vary according to the varying state of the body. Everyone shapes his actions according to his emotion, those who are assailed by conflicting emotions know not what they wish ; those who are not attacked by any emotion are readily swayed this way or that. All these considerations clearly show that a mental decision and a bodily appetite, or determined state, are simultaneous, or rather are one and the same thing, which we call decision, when it is regarded under and explained through the attribute of thought, and a conditioned state, when it is regarded under the attribute of extension, and deduced from the laws of motion and rest. This will appear yet more plainly in the sequel. For the present I wish to call attention to another point, namely, that we cannot act by the decision of the mind, unless we have a remembrance of having done so. For instance, we cannot say a word without remembering that we have done so. Again, it is not within the free power of the mind to remember or forget a thing at will. Therefore the freedom of the mind must in any case be limited to the power of uttering or not uttering something which it remembers. But when we dream that we speak, we believe that we speak from a free decision of the mind, yet we do not speak, or, if we do, it is by a spontaneous motion of the body. Again, we dream that we are concealing something, and we seem to act from the same decision of the mind as that, whereby we keep silence when awake concerning something we know. Lastly, we dream that from the free decision of our mind we do something, which we should not dare to do when awake. Now I should like to know whether there be in the mind two sorts of decisions, one sort illusive, and the other sort free? If our folly does not carry us so far as this, we must necessarily admit, that the decision of the mind, which is believed to be free, is not distinguishable from the imagination or memory, and is nothing more than the affirmation, which an idea, by virtue of being an idea, necessarily involves (II. xlix.). Wherefore these decisions of the mind arise in the mind by the same necessity, as the ideas of things actually existing. Therefore those who believe, that they speak or keep silence or act in any way from the free decision of their mind, do but dream with their eyes open.
PROP. III. The activities of the mind arise solely from adequate ideas ; the passive states of the mind depend solely on inadequate ideas.
Proof.-The first element, which constitutes the essence of the mind, is nothing else but the idea of the actually existent body (II. xi. and xiii.), which (II. xv.) is compounded of many other ideas, whereof some are adequate and some inadequate (II. xxix. Coroll., II. xxxviii. Coroll.). Whatsoever therefore follows from the nature of mind, and has mind for its proximate cause, through which it must be understood, must necessarily follow either from an adequate or from an inadequate idea. But in so far as the mind (III. i.) has inadequate ideas, it is necessarily passive : wherefore the activities of the mind follow solely from adequate ideas, and accordingly the mind is only passive in so far as it has inadequate ideas. Q.E.D. Note.-Thus we see, that passive states are not attributed to the mind, except in so far as it contains something involving negation, or in so far as it is regarded as a part of nature, which cannot be clearly and distinctly perceived through itself without other parts : I could thus show, that passive states are attributed to individual things in the same way that they are attributed to the mind, and that they cannot otherwise be perceived, but my purpose is solely to treat of the human mind.
PROP. IV. Nothing can be destroyed, except by a cause external to itself.
Proof.-This proposition is self-evident, for the definition of anything affirms the essence of that thing, but does not negative it ; in other words, it postulates the essence of the thing, but does not take it away. So long therefore as we regard only the thing itself, without taking into account external causes, we shall not be able to find in it anything which could destroy it. Q.E.D.
PROP. V. Things are naturally contrary, that is, cannot exist in the same object, in so far as one is capable of destroying the other.
Proof.-If they could agree together or co-exist in the same object, there would then be in the said object something which could destroy it ; but this, by the foregoing proposition, is absurd, therefore things, &c. Q.E.D.
PROP. VI. Everything, in so far as it is in itself, endeavours to persist in its own being.
Proof.-Individual things are modes whereby the attributes of God are expressed in a given determinate manner (I. xxv. Coroll.) ; that is, (I. xxxiv.), they are things which express in a given determinate manner the power of God, whereby God is and acts ; now no thing contains in itself anything whereby it can be destroyed, or which can take away its existence (III. iv.) ; but contrariwise it is opposed to all that could take away its existence (III. v.). Therefore, in so far as it can, and in so far as it is in itself, it endeavours to persist in its own being. Q.E.D.
PROP. VII. The endeavour, wherewith everything endeavours to persist in its own being, is nothing else but the actual essence of the thing in question.
Proof.-From the given essence of any thing certain consequences necessarily follow (I. xxxvi.), nor have things any power save such as necessarily follows from their nature as determined (I. xxix.) ; wherefore the power of any given thing, or the endeavour whereby, either alone or with other things, it acts, or endeavours to act, that is (III. vi.), the power or endeavour, wherewith it endeavours to persist in its own being, is nothing else but the given or actual essence of the thing in question. Q.E.D.
PROP. VIII. The endeavour, whereby a thing endeavours to persist in its own being, involves no finite time, but an indefinite time.
Proof.-If it involved a limited time, which should determine the duration of the thing, it would then follow solely from that power whereby the thing exists, that the thing could not exist beyond the limits of that time, but that it must be destroyed ; but this (III. iv.) is absurd. Wherefore the endeavour wherewith a thing exists involves no definite time ; but, contrariwise, since (III. iv.) it will by the same power whereby it already exists always continue to exist, unless it be destroyed by some external cause, this endeavour involves an indefinite time.
PROP. IX. The mind, both in so far as it has clear and distinct ideas, and also in so far as it has confused ideas, endeavours to persist in its being for an indefinite period, and of this endeavour it is conscious.
Proof.-The essence of the mind is constituted by adequate and inadequate ideas (III. iii.), therefore (III. vii.), both in so far as it possesses the former, and in so far as it possesses the latter, it endeavours to persist in its own being, and that for an indefinite time (III. viii.). Now as the mind (II. xxiii.) is necessarily conscious of itself through the ideas of the modifications of the body, the mind is therefore (III. vii.) conscious of its own endeavour.
Note.-This endeavour, when referred solely to the mind, is called will, when referred to the mind and body in conjunction it is called appetite ; it is, in fact, nothing else but man’s essence, from the nature of which necessarily follow all those results which tend to its preservation ; and which man has thus been determined to perform.
Further, between appetite and desire there is no difference, except that the term desire is generally applied to men, in so far as they are conscious of their appetite, and may accordingly be thus defined : Desire is appetite with consciousness thereof. It is thus plain from what has been said, that in no case do we strive for, wish for, long for, or desire anything, because we deem it to be good, but on the other hand we deem a thing to be good, because we strive for it, wish for it, long for it, or desire it.
PROP. X. An idea, which excludes the existence of our body, cannot be postulated in our mind, but is contrary thereto. Proof.-Whatsoever can destroy our body, cannot be postulated therein (III. v.). Therefore neither can the idea of such a thing occur in God, in so far as he has the idea of our body (II. ix. Coroll.) ; that is (II.xi., xiii.), the idea of that thing cannot be postulated as in our mind, but contrariwise, since (II. xi., xiii.) the first element, that constitutes the essence of the mind, is the idea of the human body as actually existing, it follows that the first and chief endeavour of our mind is the endeavour to affirm the existence of our body : thus, an idea, which negatives the existence of our body, is contrary to our mind, &c. Q.E.D.
PROP. XI. Whatsoever increases or diminishes, helps or hinders the power of activity in our body, the idea thereof increases or diminishes, helps or hinders the power of thought in our mind. Proof.-This proposition is evident from II. vii. or from II. xiv.
Note.-Thus we see, that the mind can undergo many changes, and can pass sometimes to a state of greater perfection, sometimes to a state of lesser perfection. These passive states of transition explain to us the emotions of pleasure and pain. By pleasure therefore in the following propositions I shall signify a passive state wherein the mind passes to a greater perfection. By pain I shall signify a passive state wherein the mind passes to a lesser perfection. Further, the emotion of pleasure in reference to the body and mind together I shall call stimulation (titillatio) or merriment (hilaritas), the emotion of pain in the same relation I shall call suffering or melancholy. But we must bear in mind, that stimulation and suffering are attributed to man, when one part of his nature is more affected than the rest, merriment and melancholy, when all parts are alike affected. What I mean by desire I have explained in the note to Prop. ix. of this part ; beyond these three I recognize no other primary emotion ; I will show as I proceed, that all other emotions arise from these three. But, before I go further, I should like here to explain at greater length Prop. x of this part, in order that we may clearly understand how one idea is contrary to another. In the note to II. xvii. we showed that the idea, which constitutes the essence of mind, involves the existence of body, so long as the body itself exists. Again, it follows from what we pointed out in the Corollary to II. viii., that the present existence of our mind depends solely on the fact, that the mind involves the actual existence of the body. Lastly, we showed (II. xvii., xviii. and note) that the power of the mind, whereby it imagines and remembers things, also depends on the fact, that it involves the actual existence of the body. Whence it follows, that the present existence of the mind and its power of imagining are removed, as soon as the mind ceases to affirm the present existence of the body. Now the cause, why the mind ceases to affirm this existence of the body, cannot be the mind itself (III. iv.), nor again the fact that the body ceases to exist. For (by II. vi.) the cause, why the mind affirms the existence of the body, is not that the body began to exist ; therefore, for the same reason, it does not cease to affirm the existence of the body, because the body ceases to exist ; but (II. xvii.) this result follows from another idea, which excludes the present existence of our body and, consequently, of our mind, and which is therefore contrary to the idea constituting the essence of our mind.
PROP. XII. The mind, as far as it can, endeavours to conceive those things, which increase or help the power of activity in the body.
Proof.-So long as the human body is affected in a mode, which involves the nature of any external body, the human mind will regard that external body as present (II. xvii.), and consequently (II. vii.), so long as the human mind regards an external body as present, that is (II. xvii. note), conceives it, the human body is affected in a mode, which involves the nature of the said external body ; thus so long as the mind conceives things, which increase or help the power of activity in our body, the body is affected in modes which increase or help its power of activity (III. Post. i.) ; consequently (III. xi.) the mind’s power of thinking is for that period increased or helped. Thus (III. vi., ix.) the mind, as far as it can, endeavours to imagine such things. Q.E.D.
PROP. XIII. When the mind conceives things which diminish or hinder the body’s power of activity, it endeavours, as far as possible, to remember things which exclude the existence of the first-named things.
Proof.-So long as the mind conceives anything of the kind alluded to, the power of the mind and body is diminished or constrained (cf. III. xii. Proof) ; nevertheless it will continue to conceive it, until the mind conceives something else, which excludes the present existence thereof (II. xvii.) ; that is (as I have just shown), the power of the mind and of the body is diminished, or constrained, until the mind conceives something else, which excludes the existence of the former thing conceived : therefore the mind (III. ix.), as far as it can, will endeavour to conceive or remember the latter. Q.E.D. Corollary.-Hence it follows that the mind shrinks from conceiving those things, which diminish or constrain the power of itself and of the body.
Note.-From what has been said we may clearly understand the nature of Love and Hate. Love is nothing else but pleasure accompanied by the idea of an external cause : Hate is nothing else but pain accompanied by the idea of an external cause. We further see, that he who loves necessarily endeavours to have, and to keep present to him, the object of his love ; while he who hates endeavours to remove and destroy the object of his hatred. But I will treat of these matters at more length hereafter.
PROP. XIV. If the mind has once been affected by two emotions at the same time, it will, whenever it is afterwards affected by one of these two, be also affected by the other. Proof.-If the human body has once been affected by two bodies at once, whenever afterwards the mind conceives one of them, it will straightway remember the other also (II. xviii.). But the mind’s conceptions indicate rather the emotions of our body than the nature of external bodies (II. xvi. Coroll. ii.) ; therefore, if the body, and consequently the mind (III. Def. iii.) has been once affected by two emotions at the same time, it will, whenever it is afterwards affected by one of the two, be also affected by the other.
PROP. XV. Anything can, accidentally, be the cause of pleasure, pain, or desire.
Proof.-Let it be granted that the mind is simultaneously affected by two emotions, of which one neither increases nor diminishes its power of activity, and the other does either increase or diminish the said power (III. Post. i.). From the foregoing proposition it is evident that, whenever the mind is afterwards affected by the former, through its true cause, which (by hypothesis) neither increases nor diminishes its power of action, it will be at the same time affected by the latter, which does increase or diminish its power of activity, that is (III. xi. note) it will be affected with pleasure or pain. Thus the former of the two emotions will, not through itself, but accidentally, be the cause of pleasure or pain. In the same way also it can be easily shown, that a thing may be accidentally the cause of desire. Q.E.D.
Corollary.-Simply from the fact that we have regarded a thing with the emotion of pleasure or pain, though that thing be not the efficient cause of the emotion, we can either love or hate it.
Proof.-For from this fact alone it arises (III. xiv.), that the mind afterwards conceiving the said thing is affected with the emotion of pleasure or pain, that is (III. xi. note), according as the power of the mind and body may be increased or diminished, &c. ; and consequently (III. xii.), according as the mind may desire or shrink from the conception of it (III. xiii. Coroll.), in other words (III. xiii. note), according as it may love or hate the same. Q.E.D.
Note.-Hence we understand how it may happen, that we love or hate a thing without any cause for our emotion being known to us ; merely, as a phrase is, from sympathy or antipathy. We should refer to the same category those objects, which affect us pleasurably or painfully, simply because they resemble other objects which affect us in the same way. This I will show in the next Prop. I am aware that certain authors, who were the first to introduce these terms “sympathy” and “antipathy,” wished to signify thereby some occult qualities in things ; nevertheless I think we may be permitted to use the same terms to indicate known or manifest qualities.
PROP. XVI. Simply from the fact that we conceive, that a given object has some point of resemblance with another object which is wont to affect the mind pleasurably or painfully, although the point of resemblance be not the efficient cause of the said emotions, we shall still regard the first-named object with love or hate.
Proof.-The point of resemblance was in the object (by hypothesis), when we regarded it with pleasure or pain, thus (III. xiv.), when the mind is affected by the image thereof, it will straightway be affected by one or the other emotion, and consequently the thing, which we perceive to have the same point of resemblance, will be accidentally (III. xv.) a cause of pleasure or pain. Thus (by the foregoing Corollary), although the point in which the two objects resemble one another be not the efficient cause of the emotion, we shall still regard the first-named object with love or hate. Q.E.D.
PROP. XVII. If we conceive that a thing, which is wont to affect us painfully, has any point of resemblance with another thing which is wont to affect us with an equally strong emotion of pleasure, we shall hate the first-named thing, and at the same time we shall love it.
Proof.-The given thing is (by hypothesis) in itself a cause of pain, and (III. xiii. note), in so far as we imagine it with this emotion, we shall hate it : further, inasmuch as we conceive that it has some point of resemblance to something else, which is wont to affect us with an equally strong emotion of pleasure, we shall with an equally strong impulse of pleasure love it (III.xvi.) ; thus we shall both hate and love the same thing. Q.E.D.
Note.-This disposition of the mind, which arises from two contrary emotions, is called vacillation ; it stands to the emotions in the same relation as doubt does to the imagination (II. xliv. note) ; vacillation and doubt do not differ one from the other, except as greater differs from less. But we must bear in mind that I have deduced this vacillation from causes, which give rise through themselves to one of the emotions, and to the other accidentally. I have done this, in order that they might be more easily deduced from what went before ; but I do not deny that vacillation of the disposition generally arises from an object, which is the efficient cause of both emotions. The human body is composed (II. Post. i.) of a variety of individual parts of different nature, and may therefore (Ax.i. after Lemma iii. after II. xiii.) be affected in a variety of different ways by one and the same body ; and contrariwise, as one and the same thing can be affected in many ways, it can also in many different ways affect one and the same part of the body. Hence we can easily conceive, that one and the same object may be the cause of many and conflicting emotions.
PROP. XVIII. A man is as much affected pleasurably or painfully by the image of a thing past or future as by the image of a thing present.
Proof.-So long as a man is affected by the image of anything, he will regard that thing as present, even though it be non-existent (II. xvii. and Coroll.), he will not conceive it as past or future, except in so far as its image is joined to the image of time past or future (II. xliv. note). Wherefore the image of a thing, regarded in itself alone, is identical, whether it be referred to time past, time future, or time present ; that is (II. xvi. Coroll.), the disposition or emotion of the body is identical, whether the image be of a thing past, future, or present. Thus the emotion of pleasure or pain is the ssame, whether the image be of a thing past or future. Q.E.D. Note I.-I call a thing past or future, according as we either have been or shall be affected thereby. For instance, according as we have seen it, or are about to see it, according as it has recreated us, or will recreate us, according as it has harmed us, or will harm us. For, as we thus conceive it, we affirm its existence ; that is, the body is affected by no emotion which excludes the existence of the thing, and therefore (II. xvii.) the body is affected by the image of the thing, in the same way as if the thing were actually present. However, as it generally happens that those, who have had many experiences, vacillate, so long as they regard a thing as future or past, and are usually in doubt about its issue (II. xliv. note) ; it follows that the emotions which arise from similar images of things are not so constant, but are generally disturbed by the images of other things, until men become assured of the issue. Note II.-From what has just been said, we understand what is meant by the terms Hope, Fear, Confidence, Despair, Joy, and Disappointment.5 Hope is nothing else but an inconstant pleasure, arising from the image of something future or past, whereof we do not yet know the issue. Fear, on the other hand, is an inconstant pain also arising from the image of something concerning which we are in doubt. If the element of doubt be removed from these emotions, hope becomes Confidence and fear becomes Despair. In other words, Pleasure or Pain arising from the image of something concerning which we have hoped or feared. Again, Joy is Pleasure arising from the image of something past whereof we have doubted the issue. Disappointment is the Pain opposed to Joy.
PROP. XIX. He who conceives that the object of his love is destroyed will feel pain ; if he conceives that it is preserved he will feel pleasure.
Proof.-The mind, as far as possible, endeavours to conceive those things which increase or help the body’s power of activity (III. xii.) ; in other words (III. xii. note), those things which it loves. But conception is helped by those things which postulate the existence of a thing, and contrariwise is hindered by those which exclude the existence of a thing (II. xvii.) ; therefore the images of things, which postulate the existence of an object of love, help the mind’s endeavour to conceive the object of love, in other words (III. xi. note), affect the mind pleasurably ; contrariwise those things, which exclude the existence of an object of love, hinder the aforesaid mental endeavour ; in other words, affect the mind painfully. He, therefore, who conceives that the object of his love is destroyed will feel pain, &c. Q.E.D.
PROP. XX. He who conceives that the object of his hate is destroyed will also feel pleasure.
Proof.-The mind (III. xiii.) endeavours to conceive those things, which exclude the existence of things whereby the body’s power of activity is diminished or constrained ; that is (III. xiii. note), it endeavours to conceive such things as exclude the existence of what it hates ; therefore the image of a thing, which excludes the existence of what the mind hates, helps the aforesaid mental effort, in other words (III. xi. note), affects the mind pleasurably. Thus he who conceives that the object of his hate is destroyed will feel pleasure. Q.E.D.
PROP. XXI. He who conceives, that the object of his love is affected pleasurably or painfully, will himself be affected pleasurably or painfully ; and the one or the other emotion will be greater or less in the lover according as it is greater or less in the thing loved.
Proof.-The images of things (as we showed in III. xix.) which postulate the existence of the object of love, help the mind’s endeavour to conceive the said object. But pleasure postulates the existence of something feeling pleasure, so much the more in proportion as the emotion of pleasure is greater ; for it is (III. xi. note) a transition to a greater perfection ; therefore the image of pleasure in the object of love helps the mental endeavour of the lover ; that is, it affects the lover pleasurably, and so much the more, in proportion as this emotion may have been greater in the object of love. This was our first point. Further, in so far as a thing is affected with pain, it is to that extent destroyed, the extent being in proportion to the amount of pain (III. xi. note) ; therefore (III. xix.) he who conceives, that the object of his love is affected painfully, will himself be affected painfully, in proportion as the said emotion is greater or less in the object of love. Q.E.D.
PROP. XXII. If we conceive that anything pleasurably affects some object of our love, we shall be affected with love towards that thing. Contrariwise, if we conceive that it affects an object of our love painfully, we shall be affected with hatred towards it.
Proof.-He, who affects pleasurably or painfully the object of our love, affects us also pleasurably or painfully-that is, if we conceive the loved object as affected with the said pleasure or pain (III. xxi.). But this pleasure or pain is postulated to come to us accompanied by the idea of an external cause ; therefore (III. xiii. note), if we conceive that anyone affects an object of our love pleasurably or painfully, we shall be affected with love or hatred towards him. Q.E.D.
Note.-Prop. xxi. explains to us the nature of Pity, which we may define as pain arising from another’s hurt. What term we can use for pleasure arising from another’s gain, I know not. We will call the love towards him who confers a benefit on another, Approval ; and the hatred towards him who injures another, we will call Indignation. We must further remark, that we not only feel pity for a thing which we have loved (as shown in III. xxi.), but also for a thing which we have hitherto regarded without emotion, provided that we deem that it resembles ourselves (as I will show presently). Thus, we bestow approval on one who has benefited anything resembling ourselves, and, contrariwise, are indignant with him who has done it an injury.
PROP. XXIII. He who conceives, that an object of his hatred is painfully affected, will feel pleasure. Contrariwise, if he thinks that the said object is pleasurably affected, he will feel pain. Each of these emotions will be greater or less, according as its contrary is greater or less in the object of hatred. Proof.-In so far as an object of hatred is painfully