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The Critique of Pure Reason by Immanuel Kant

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All the powers of reason, in the sphere of what may be termed pure
philosophy, are, in fact, directed to the three above-mentioned
problems alone. These again have a still higher end--the answer to
the question, what we ought to do, if the will is free, if there is
a God and a future world. Now, as this problem relates to our in
reference to the highest aim of humanity, it is evident that the
ultimate intention of nature, in the constitution of our reason, has
been directed to the moral alone.

We must take care, however, in turning our attention to an object
which is foreign* to the sphere of transcendental philosophy, not to
injure the unity of our system by digressions, nor, on the other hand,
to fail in clearness, by saying too little on the new subject of
discussion. I hope to avoid both extremes, by keeping as close as
possible to the transcendental, and excluding all psychological,
that is, empirical, elements.

[*Footnote: All practical conceptions relate to objects of pleasure
and pain, and consequently--in an indirect manner, at least--to objects
of feeling. But as feeling is not a faculty of representation, but
lies out of the sphere of our powers of cognition, the elements of
our judgements, in so far as they relate to pleasure or pain, that
is, the elements of our practical judgements, do not belong to
transcendental philosophy, which has to do with pure a priori
cognitions alone.]

I have to remark, in the first place, that at present I treat of the
conception of freedom in the practical sense only, and set aside the
corresponding transcendental conception, which cannot be employed as
a ground of explanation in the phenomenal world, but is itself a problem
for pure reason. A will is purely animal (arbitrium brutum) when it
is determined by sensuous impulses or instincts only, that is, when
it is determined in a pathological manner. A will, which can be determined
independently of sensuous impulses, consequently by motives
presented by reason alone, is called a free will (arbitrium
liberum); and everything which is connected with this free will,
either as principle or consequence, is termed practical. The existence
of practical freedom can be proved from experience alone. For the
human will is not determined by that alone which immediately affects
the senses; on the contrary, we have the power, by calling up the
notion of what is useful or hurtful in a more distant relation, of
overcoming the immediate impressions on our sensuous faculty of
desire. But these considerations of what is desirable in relation to
our whole state, that is, is in the end good and useful, are based
entirely upon reason. This faculty, accordingly, enounces laws,
which are imperative or objective laws of freedom and which tell us
what ought to take place, thus distinguishing themselves from the laws
of nature, which relate to that which does take place. The laws of
freedom or of free will are hence termed practical laws.

Whether reason is not itself, in the actual delivery of these
laws, determined in its turn by other influences, and whether the
action which, in relation to sensuous impulses, we call free, may not,
in relation to higher and more remote operative causes, really form
a part of nature--these are questions which do not here concern us.
They are purely speculative questions; and all we have to do, in the
practical sphere, is to inquire into the rule of conduct which
reason has to present. Experience demonstrates to us the existence
of practical freedom as one of the causes which exist in nature,
that is, it shows the causal power of reason in the determination of
the will. The idea of transcendental freedom, on the contrary,
requires that reason--in relation to its causal power of commencing
a series of phenomena--should be independent of all sensuous
determining causes; and thus it seems to be in opposition to the law
of nature and to all possible experience. It therefore remains a
problem for the human mind. But this problem does not concern reason
in its practical use; and we have, therefore, in a canon of pure
reason, to do with only two questions, which relate to the practical
interest of pure reason: Is there a God? and, Is there a future
life? The question of transcendental freedom is purely speculative,
and we may therefore set it entirely aside when we come to treat of
practical reason. Besides, we have already discussed this subject in
the antinomy of pure reason.

SECTION II. Of the Ideal of the Summum Bonum as a Determining
Ground of the Ultimate End of Pure Reason.

Reason conducted us, in its speculative use, through the field of
experience and, as it can never find complete satisfaction in that
sphere, from thence to speculative ideas--which, however, in the end
brought us back again to experience, and thus fulfilled the purpose
of reason, in a manner which, though useful, was not at all in accordance
with our expectations. It now remains for us to consider whether
pure reason can be employed in a practical sphere, and whether it will
here conduct us to those ideas which attain the highest ends of pure
reason, as we have just stated them. We shall thus ascertain
whether, from the point of view of its practical interest, reason
may not be able to supply us with that which, on the speculative side,
it wholly denies us.

The whole interest of reason, speculative as well as practical, is
centred in the three following questions:


The first question is purely speculative. We have, as I flatter
myself, exhausted all the replies of which it is susceptible, and have
at last found the reply with which reason must content itself, and
with which it ought to be content, so long as it pays no regard to
the practical. But from the two great ends to the attainment of which
all these efforts of pure reason were in fact directed, we remain just
as far removed as if we had consulted our ease and declined the task
at the outset. So far, then, as knowledge is concerned, thus much,
at least, is established, that, in regard to those two problems, it
lies beyond our reach.

The second question is purely practical. As such it may indeed
fall within the province of pure reason, but still it is not
transcendental, but moral, and consequently cannot in itself form
the subject of our criticism.

The third question: If I act as I ought to do, what may I then
hope?--is at once practical and theoretical. The practical forms a
clue to the answer of the theoretical, and--in its highest form-
speculative question. For all hoping has happiness for its object
and stands in precisely the same relation to the practical and the
law of morality as knowing to the theoretical cognition of things and
the law of nature. The former arrives finally at the conclusion that
something is (which determines the ultimate end), because something
ought to take place; the latter, that something is (which operates
as the highest cause), because something does take place.

Happiness is the satisfaction of all our desires; extensive, in
regard to their multiplicity; intensive, in regard to their degree;
and protensive, in regard to their duration. The practical law based
on the motive of happiness I term a pragmatical law (or prudential
rule); but that law, assuming such to exist, which has no other motive
than the worthiness of being happy, I term a moral or ethical law.
The first tells us what we have to do, if we wish to become possessed
of happiness; the second dictates how we ought to act, in order to
deserve happiness. The first is based upon empirical principles; for
it is only by experience that I can learn either what inclinations
exist which desire satisfaction, or what are the natural means of
satisfying them. The second takes no account of our desires or the
means of satisfying them, and regards only the freedom of a rational
being, and the necessary conditions under which alone this freedom
can harmonize with the distribution of happiness according to
principles. This second law may therefore rest upon mere ideas of pure
reason, and may be cognized a priori.

I assume that there are pure moral laws which determine, entirely
a priori (without regard to empirical motives, that is, to happiness),
the conduct of a rational being, or in other words, to use which it
makes of its freedom, and that these laws are absolutely imperative
(not merely hypothetically, on the supposition of other empirical
ends), and therefore in all respects necessary. I am warranted in
assuming this, not only by the arguments of the most enlightened
moralists, but by the moral judgement of every man who will make the
attempt to form a distinct conception of such a law.

Pure reason, then, contains, not indeed in its speculative, but in
its practical, or, more strictly, its moral use, principles of the
possibility of experience, of such actions, namely, as, in
accordance with ethical precepts, might be met with in the history
of man. For since reason commands that such actions should take place,
it must be possible for them to take place; and hence a particular
kind of systematic unity--the moral--must be possible. We have
found, it is true, that the systematic unity of nature could not be
established according to speculative principles of reason, because,
while reason possesses a causal power in relation to freedom, it has
none in relation to the whole sphere of nature; and, while moral
principles of reason can produce free actions, they cannot produce
natural laws. It is, then, in its practical, but especially in its
moral use, that the principles of pure reason possess objective

I call the world a moral world, in so far as it may be in accordance
with all the ethical laws--which, by virtue of the freedom of
reasonable beings, it can be, and according to the necessary laws of
morality it ought to be. But this world must be conceived only as an
intelligible world, inasmuch as abstraction is therein made of all
conditions (ends), and even of all impediments to morality (the
weakness or pravity of human nature). So far, then, it is a mere idea-
though still a practical idea--which may have, and ought to have, an
influence on the world of sense, so as to bring it as far as
possible into conformity with itself. The idea of a moral world has,
therefore, objective reality, not as referring to an object of
intelligible intuition--for of such an object we can form no
conception whatever--but to the world of sense--conceived, however,
as an object of pure reason in its practical use--and to a corpus
mysticum of rational beings in it, in so far as the liberum
arbitrium of the individual is placed, under and by virtue of moral
laws, in complete systematic unity both with itself and with the
freedom of all others.

That is the answer to the first of the two questions of pure
reason which relate to its practical interest: Do that which will
render thee worthy of happiness. The second question is this: If I
conduct myself so as not to be unworthy of happiness, may I hope
thereby to obtain happiness? In order to arrive at the solution of
this question, we must inquire whether the principles of pure
reason, which prescribe a priori the law, necessarily also connect
this hope with it.

I say, then, that just as the moral principles are necessary
according to reason in its practical use, so it is equally necessary
according to reason in its theoretical use to assume that every one
has ground to hope for happiness in the measure in which he has made
himself worthy of it in his conduct, and that therefore the system
of morality is inseparably (though only in the idea of pure reason)
connected with that of happiness.

Now in an intelligible, that is, in the moral world, in the
conception of which we make abstraction of all the impediments to
morality (sensuous desires), such a system of happiness, connected
with and proportioned to morality, may be conceived as necessary,
because freedom of volition--partly incited, and partly restrained
by moral laws--would be itself the cause of general happiness; and
thus rational beings, under the guidance of such principles, would
be themselves the authors both of their own enduring welfare and
that of others. But such a system of self-rewarding morality is only
an idea, the carrying out of which depends upon the condition that
every one acts as he ought; in other words, that all actions of
reasonable beings be such as they would be if they sprung from a
Supreme Will, comprehending in, or under, itself all particular wills.
But since the moral law is binding on each individual in the use of
his freedom of volition, even if others should not act in conformity
with this law, neither the nature of things, nor the causality of
actions and their relation to morality, determine how the consequences
of these actions will be related to happiness; and the necessary
connection of the hope of happiness with the unceasing endeavour to
become worthy of happiness, cannot be cognized by reason, if we take
nature alone for our guide. This connection can be hoped for only on
the assumption that the cause of nature is a supreme reason, which
governs according to moral laws.

I term the idea of an intelligence in which the morally most perfect
will, united with supreme blessedness, is the cause of all happiness
in the world, so far as happiness stands in strict relation to
morality (as the worthiness of being happy), the ideal of the
supreme Good. supreme original good, that pure reason can find the
ground of the practically necessary connection of both elements of
the highest derivative good, and accordingly of an intelligible, that
is, moral world. Now since we are necessitated by reason to conceive
ourselves as belonging to such a world, while the senses present to
us nothing but a world of phenomena, we must assume the former as a
consequence of our conduct in the world of sense (since the world of
sense gives us no hint of it), and therefore as future in relation
to us. Thus God and a future life are two hypotheses which,
according to the principles of pure reason, are inseparable from the
obligation which this reason imposes upon us.

Morality per se constitutes a system. But we can form no system of
happiness, except in so far as it is dispensed in strict proportion
to morality. But this is only possible in the intelligible world, under
a wise author and ruler. Such a ruler, together with life in such a
world, which we must look upon as future, reason finds itself
compelled to assume; or it must regard the moral laws as idle
dreams, since the necessary consequence which this same reason
connects with them must, without this hypothesis, fall to the
ground. Hence also the moral laws are universally regarded as
commands, which they could not be did they not connect a priori
adequate consequences with their dictates, and thus carry with them
promises and threats. But this, again, they could not do, did they
not reside in a necessary being, as the Supreme Good, which alone can
render such a teleological unity possible.

Leibnitz termed the world, when viewed in relation to the rational
beings which it contains, and the moral relations in which they
stand to each other, under the government of the Supreme Good, the
kingdom of Grace, and distinguished it from the kingdom of Nature,
in which these rational beings live, under moral laws, indeed, but
expect no other consequences from their actions than such as follow
according to the course of nature in the world of sense. To view
ourselves, therefore, as in the kingdom of grace, in which all
happiness awaits us, except in so far as we ourselves limit our
participation in it by actions which render us unworthy of
happiness, is a practically necessary idea of reason.

Practical laws, in so far as they are subjective grounds of actions,
that is, subjective principles, are termed maxims. The judgements of
moral according to in its purity and ultimate results are framed
according ideas; the observance of its laws, according to according
to maxims.

The whole course of our life must be subject to moral maxims; but
this is impossible, unless with the moral law, which is a mere idea,
reason connects an efficient cause which ordains to all conduct
which is in conformity with the moral law an issue either in this or
in another life, which is in exact conformity with our highest aims.
Thus, without a God and without a world, invisible to us now, but
hoped for, the glorious ideas of morality are, indeed, objects of
approbation and of admiration, but cannot be the springs of purpose
and action. For they do not satisfy all the aims which are natural
to every rational being, and which are determined a priori by pure
reason itself, and necessary.

Happiness alone is, in the view of reason, far from being the
complete good. Reason does not approve of it (however much inclination
may desire it), except as united with desert. On the other hand,
morality alone, and with it, mere desert, is likewise far from being
the complete good. To make it complete, he who conducts himself in
a manner not unworthy of happiness, must be able to hope for the
possession of happiness. Even reason, unbiased by private ends, or
interested considerations, cannot judge otherwise, if it puts itself
in the place of a being whose business it is to dispense all happiness
to others. For in the practical idea both points are essentially
combined, though in such a way that participation in happiness is
rendered possible by the moral disposition, as its condition, and
not conversely, the moral disposition by the prospect of happiness.
For a disposition which should require the prospect of happiness as
its necessary condition would not be moral, and hence also would not
be worthy of complete happiness--a happiness which, in the view of
reason, recognizes no limitation but such as arises from our own
immoral conduct.

Happiness, therefore, in exact proportion with the morality of
rational beings (whereby they are made worthy of happiness),
constitutes alone the supreme good of a world into which we absolutely
must transport ourselves according to the commands of pure but
practical reason. This world is, it is true, only an intelligible
world; for of such a systematic unity of ends as it requires, the
world of sense gives us no hint. Its reality can be based on nothing
else but the hypothesis of a supreme original good. In it
independent reason, equipped with all the sufficiency of a supreme
cause, founds, maintains, and fulfils the universal order of things,
with the most perfect teleological harmony, however much this order
may be hidden from us in the world of sense.

This moral theology has the peculiar advantage, in contrast with
speculative theology, of leading inevitably to the conception of a
sole, perfect, and rational First Cause, whereof speculative
theology does not give us any indication on objective grounds, far
less any convincing evidence. For we find neither in transcendental
nor in natural theology, however far reason may lead us in these,
any ground to warrant us in assuming the existence of one only
Being, which stands at the head of all natural causes, and on which
these are entirely dependent. On the other band, if we take our
stand on moral unity as a necessary law of the universe, and from this
point of view consider what is necessary to give this law adequate
efficiency and, for us, obligatory force, we must come to the
conclusion that there is one only supreme will, which comprehends
all these laws in itself. For how, under different wills, should we
find complete unity of ends? This will must be omnipotent, that all
nature and its relation to morality in the world may be subject to
it; omniscient, that it may have knowledge of the most secret feelings
and their moral worth; omnipresent, that it may be at hand to supply
every necessity to which the highest weal of the world may give rise;
eternal, that this harmony of nature and liberty may never fail; and
so on.

But this systematic unity of ends in this world of intelligences-
which, as mere nature, is only a world of sense, but, as a system of
freedom of volition, may be termed an intelligible, that is, moral
world (regnum gratiae)--leads inevitably also to the teleological
unity of all things which constitute this great whole, according to
universal natural laws--just as the unity of the former is according
to universal and necessary moral laws--and unites the practical with
the speculative reason. The world must be represented as having
originated from an idea, if it is to harmonize with that use of reason
without which we cannot even consider ourselves as worthy of reason-
namely, the moral use, which rests entirely on the idea of the supreme
good. Hence the investigation of nature receives a teleological
direction, and becomes, in its widest extension, physico-theology.
But this, taking its rise in moral order as a unity founded on the
essence of freedom, and not accidentally instituted by external commands,
establishes the teleological view of nature on grounds which must be
inseparably connected with the internal possibility of things. This
gives rise to a transcendental theology, which takes the ideal of
the highest ontological perfection as a principle of systematic unity;
and this principle connects all things according to universal and
necessary natural laws, because all things have their origin in the
absolute necessity of the one only Primal Being.

What use can we make of our understanding, even in respect of
experience, if we do not propose ends to ourselves? But the highest
ends are those of morality, and it is only pure reason that can give
us the knowledge of these. Though supplied with these, and putting
ourselves under their guidance, we can make no teleological use of
the knowledge of nature, as regards cognition, unless nature itself
has established teleological unity. For without this unity we should
not even possess reason, because we should have no school for reason,
and no cultivation through objects which afford the materials for
its conceptions. But teleological unity is a necessary unity, and
founded on the essence of the individual will itself. Hence this will,
which is the condition of the application of this unity in concreto,
must be so likewise. In this way the transcendental enlargement of
our rational cognition would be, not the cause, but merely the effect
of the practical teleology which pure reason imposes upon us.

Hence, also, we find in the history of human reason that, before the
moral conceptions were sufficiently purified and determined, and
before men had attained to a perception of the systematic unity of
ends according to these conceptions and from necessary principles,
the knowledge of nature, and even a considerable amount of intellectual
culture in many other sciences, could produce only rude and vague
conceptions of the Deity, sometimes even admitting of an astonishing
indifference with regard to this question altogether. But the more
enlarged treatment of moral ideas, which was rendered necessary by
the extreme pure moral law of our religion, awakened the interest,
and thereby quickened the perceptions of reason in relation to this
object. In this way, and without the help either of an extended
acquaintance with nature, or of a reliable transcendental insight (for
these have been wanting in all ages), a conception of the Divine Being
was arrived at, which we now bold to be the correct one, not because
speculative reason convinces us of its correctness, but because it
accords with the moral principles of reason. Thus it is to pure
reason, but only in its practical use, that we must ascribe the
merit of having connected with our highest interest a cognition, of
which mere speculation was able only to form a conjecture, but the
validity of which it was unable to establish--and of having thereby
rendered it, not indeed a demonstrated dogma, but a hypothesis
absolutely necessary to the essential ends of reason.

But if practical reason has reached this elevation, and has attained
to the conception of a sole Primal Being as the supreme good, it
must not, therefore, imagine that it has transcended the empirical
conditions of its application, and risen to the immediate cognition
of new objects; it must not presume to start from the conception which
it has gained, and to deduce from it the moral laws themselves. For
it was these very laws, the internal practical necessity of which led
us to the hypothesis of an independent cause, or of a wise ruler of
the universe, who should give them effect. Hence we are not entitled
to regard them as accidental and derived from the mere will of the
ruler, especially as we have no conception of such a will, except as
formed in accordance with these laws. So far, then, as practical
reason has the right to conduct us, we shall not look upon actions
as binding on us, because they are the commands of God, but we shall
regard them as divine commands, because we are internally bound by
them. We shall study freedom under the teleological unity which
accords with principles of reason; we shall look upon ourselves as
acting in conformity with the divine will only in so far as we hold
sacred the moral law which reason teaches us from the nature of
actions themselves, and we shall believe that we can obey that will
only by promoting the weal of the universe in ourselves and in others.
Moral theology is, therefore, only of immanent use. It teaches us to
fulfil our destiny here in the world, by placing ourselves in
harmony with the general system of ends, and warns us against the
fanaticism, nay, the crime of depriving reason of its legislative
authority in the moral conduct of life, for the purpose of directly
connecting this authority with the idea of the Supreme Being. For this
would be, not an immanent, but a transcendent use of moral theology,
and, like the transcendent use of mere speculation, would inevitably
pervert and frustrate the ultimate ends of reason.

SECTION III. Of Opinion, Knowledge, and Belief.

The holding of a thing to be true is a phenomenon in our
understanding which may rest on objective grounds, but requires, also,
subjective causes in the mind of the person judging. If a judgement
is valid for every rational being, then its ground is objectively
sufficient, and it is termed a conviction. If, on the other hand, it
has its ground in the particular character of the subject, it is
termed a persuasion.

Persuasion is a mere illusion, the ground of the judgement, which
lies solely in the subject, being regarded as objective. Hence a
judgement of this kind has only private validity--is only valid for
the individual who judges, and the holding of a thing to be true in
this way cannot be communicated. But truth depends upon agreement with
the object, and consequently the judgements of all understandings,
if true, must be in agreement with each other (consentientia uni
tertio consentiunt inter se). Conviction may, therefore, be
distinguished, from an external point of view, from persuasion, by
the possibility of communicating it and by showing its validity for
the reason of every man; for in this case the presumption, at least,
arises that the agreement of all judgements with each other, in
spite of the different characters of individuals, rests upon the
common ground of the agreement of each with the object, and thus the
correctness of the judgement is established.

Persuasion, accordingly, cannot be subjectively distinguished from
conviction, that is, so long as the subject views its judgement simply
as a phenomenon of its own mind. But if we inquire whether the grounds
of our judgement, which are valid for us, produce the same effect on
the reason of others as on our own, we have then the means, though
only subjective means, not, indeed, of producing conviction, but of
detecting the merely private validity of the judgement; in other
words, of discovering that there is in it the element of mere

If we can, in addition to this, develop the subjective causes of the
judgement, which we have taken for its objective grounds, and thus
explain the deceptive judgement as a phenomenon in our mind, apart
altogether from the objective character of the object, we can then
expose the illusion and need be no longer deceived by it, although,
if its subjective cause lies in our nature, we cannot hope altogether
to escape its influence.

I can only maintain, that is, affirm as necessarily valid for
every one, that which produces conviction. Persuasion I may keep for
myself, if it is agreeable to me; but I cannot, and ought not, to
attempt to impose it as binding upon others.

Holding for true, or the subjective validity of a judgement in
relation to conviction (which is, at the same time, objectively
valid), has the three following degrees: opinion, belief, and
knowledge. Opinion is a consciously insufficient judgement,
subjectively as well as objectively. Belief is subjectively
sufficient, but is recognized as being objectively insufficient.
Knowledge is both subjectively and objectively sufficient.
Subjective sufficiency is termed conviction (for myself); objective
sufficiency is termed certainty (for all). I need not dwell longer
on the explanation of such simple conceptions.

I must never venture to be of opinion, without knowing something, at
least, by which my judgement, in itself merely problematical, is
brought into connection with the truth--which connection, although
not perfect, is still something more than an arbitrary fiction.
Moreover, the law of such a connection must be certain. For if, in
relation to this law, I have nothing more than opinion, my judgement
is but a play of the imagination, without the least relation to truth.
In the judgements of pure reason, opinion has no place. For, as they
do not rest on empirical grounds and as the sphere of pure reason is
that of necessary truth and a priori cognition, the principle of
connection in it requires universality and necessity, and consequently
perfect certainty--otherwise we should have no guide to the truth at
all. Hence it is absurd to have an opinion in pure mathematics; we
must know, or abstain from forming a judgement altogether. The case
is the same with the maxims of morality. For we must not hazard an
action on the mere opinion that it is allowed, but we must know it
to be so. In the transcendental sphere of reason, on the other hand,
the term opinion is too weak, while the word knowledge is too strong.
From the merely speculative point of view, therefore, we cannot form
a judgement at all. For the subjective grounds of a judgement, such
as produce belief, cannot be admitted in speculative inquiries,
inasmuch as they cannot stand without empirical support and are
incapable of being communicated to others in equal measure.

But it is only from the practical point of view that a theoretically
insufficient judgement can be termed belief. Now the practical
reference is either to skill or to morality; to the former, when the
end proposed is arbitrary and accidental, to the latter, when it is
absolutely necessary.

If we propose to ourselves any end whatever, the conditions of its
attainment are hypothetically necessary. The necessity is
subjectively, but still only comparatively, sufficient, if I am
acquainted with no other conditions under which the end can be
attained. On the other hand, it is sufficient, absolutely and for
every one, if I know for certain that no one can be acquainted with
any other conditions under which the attainment of the proposed end
would be possible. In the former case my supposition--my judgement
with regard to certain conditions--is a merely accidental belief; in
the latter it is a necessary belief. The physician must pursue some
course in the case of a patient who is in danger, but is ignorant of
the nature of the disease. He observes the symptoms, and concludes,
according to the best of his judgement, that it is a case of phthisis.
His belief is, even in his own judgement, only contingent: another
man might, perhaps come nearer the truth. Such a belief, contingent
indeed, but still forming the ground of the actual use of means for
the attainment of certain ends, I term Pragmatical belief.

The usual test, whether that which any one maintains is merely his
persuasion, or his subjective conviction at least, that is, his firm
belief, is a bet. It frequently happens that a man delivers his
opinions with so much boldness and assurance, that he appears to be
under no apprehension as to the possibility of his being in error.
The offer of a bet startles him, and makes him pause. Sometimes it
turns out that his persuasion may be valued at a ducat, but not at
ten. For he does not hesitate, perhaps, to venture a ducat, but if
it is proposed to stake ten, he immediately becomes aware of the
possibility of his being mistaken--a possibility which has hitherto
escaped his observation. If we imagine to ourselves that we have to
stake the happiness of our whole life on the truth of any proposition,
our judgement drops its air of triumph, we take the alarm, and discover
the actual strength of our belief. Thus pragmatical belief has
degrees, varying in proportion to the interests at stake.

Now, in cases where we cannot enter upon any course of action in
reference to some object, and where, accordingly, our judgement is
purely theoretical, we can still represent to ourselves, in thought,
the possibility of a course of action, for which we suppose that we
have sufficient grounds, if any means existed of ascertaining the
truth of the matter. Thus we find in purely theoretical judgements
an analogon of practical judgements, to which the word belief may
properly be applied, and which we may term doctrinal belief. I
should not hesitate to stake my all on the truth of the proposition-
if there were any possibility of bringing it to the test of
experience--that, at least, some one of the planets, which we see,
is inhabited. Hence I say that I have not merely the opinion, but
the strong belief, on the correctness of which I would stake even many
of the advantages of life, that there are inhabitants in other worlds.

Now we must admit that the doctrine of the existence of God
belongs to doctrinal belief. For, although in respect to the
theoretical cognition of the universe I do not require to form any
theory which necessarily involves this idea, as the condition of my
explanation of the phenomena which the universe presents, but, on
the contrary, am rather bound so to use my reason as if everything
were mere nature, still teleological unity is so important a condition
of the application of my reason to nature, that it is impossible for
me to ignore it--especially since, in addition to these
considerations, abundant examples of it are supplied by experience.
But the sole condition, so far as my knowledge extends, under which
this unity can be my guide in the investigation of nature, is the
assumption that a supreme intelligence has ordered all things
according to the wisest ends. Consequently, the hypothesis of a wise
author of the universe is necessary for my guidance in the
investigation of nature--is the condition under which alone I can
fulfil an end which is contingent indeed, but by no means unimportant.
Moreover, since the result of my attempts so frequently confirms the
utility of this assumption, and since nothing decisive can be
adduced against it, it follows that it would be saying far too
little to term my judgement, in this case, a mere opinion, and that,
even in this theoretical connection, I may assert that I firmly
believe in God. Still, if we use words strictly, this must not be
called a practical, but a doctrinal belief, which the theology of
nature (physico-theology) must also produce in my mind. In the
wisdom of a Supreme Being, and in the shortness of life, so inadequate
to the development of the glorious powers of human nature, we may find
equally sufficient grounds for a doctrinal belief in the future life
of the human soul.

The expression of belief is, in such cases, an expression of modesty
from the objective point of view, but, at the same time, of firm
confidence, from the subjective. If I should venture to term this
merely theoretical judgement even so much as a hypothesis which I am
entitled to assume; a more complete conception, with regard to another
world and to the cause of the world, might then be justly required
of me than I am, in reality, able to give. For, if I assume
anything, even as a mere hypothesis, I must, at least, know so much
of the properties of such a being as will enable me, not to form the
conception, but to imagine the existence of it. But the word belief
refers only to the guidance which an idea gives me, and to its
subjective influence on the conduct of my reason, which forces me to
hold it fast, though I may not be in a position to give a
speculative account of it.

But mere doctrinal belief is, to some extent, wanting in
stability. We often quit our hold of it, in consequence of the
difficulties which occur in speculation, though in the end we
inevitably return to it again.

It is quite otherwise with moral belief. For in this sphere action
is absolutely necessary, that is, I must act in obedience to the moral
law in all points. The end is here incontrovertibly established, and
there is only one condition possible, according to the best of my
perception, under which this end can harmonize with all other ends,
and so have practical validity--namely, the existence of a God and
of a future world. I know also, to a certainty, that no one can be
acquainted with any other conditions which conduct to the same unity
of ends under the moral law. But since the moral precept is, at the
same time, my maxim (as reason requires that it should be), I am
irresistibly constrained to believe in the existence of God and in
a future life; and I am sure that nothing can make me waver in this
belief, since I should thereby overthrow my moral maxims, the
renunciation of which would render me hateful in my own eyes.

Thus, while all the ambitious attempts of reason to penetrate beyond
the limits of experience end in disappointment, there is still
enough left to satisfy us in a practical point of view. No one, it
is true, will be able to boast that he knows that there is a God and
a future life; for, if he knows this, he is just the man whom I have
long wished to find. All knowledge, regarding an object of mere
reason, can be communicated; and I should thus be enabled to hope that
my own knowledge would receive this wonderful extension, through the
instrumentality of his instruction. No, my conviction is not
logical, but moral certainty; and since it rests on subjective grounds
(of the moral sentiment), I must not even say: It is morally certain
that there is a God, etc., but: I am morally certain, that is, my
belief in God and in another world is so interwoven with my moral
nature that I am under as little apprehension of having the former
torn from me as of losing the latter.

The only point in this argument that may appear open to suspicion is
that this rational belief presupposes the existence of moral
sentiments. If we give up this assumption, and take a man who is
entirely indifferent with regard to moral laws, the question which
reason proposes, becomes then merely a problem for speculation and
may, indeed, be supported by strong grounds from analogy, but not by
such as will compel the most obstinate scepticism to give way.* But
in these questions no man is free from all interest. For though the
want of good sentiments may place him beyond the influence of moral
interests, still even in this case enough may be left to make him fear
the existence of God and a future life. For he cannot pretend to any
certainty of the non-existence of God and of a future life, unless-
since it could only be proved by mere reason, and therefore
apodeictically--he is prepared to establish the impossibility of both,
which certainly no reasonable man would undertake to do. This would
be a negative belief, which could not, indeed, produce morality and
good sentiments, but still could produce an analogon of these, by
operating as a powerful restraint on the outbreak of evil

[*Footnote: The human mind (as, I believe, every rational being must
of necessity do) takes a natural interest in morality, although this
interest is not undivided, and may not be practically in
preponderance. If you strengthen and increase it, you will find the
reason become docile, more enlightened, and more capable of uniting
the speculative interest with the practical. But if you do not take
care at the outset, or at least midway, to make men good, you will
never force them into an honest belief.]

But, it will be said, is this all that pure reason can effect, in
opening up prospects beyond the limits of experience? Nothing more
than two articles of belief? Common sense could have done as much as
this, without taking the philosophers to counsel in the matter!

I shall not here eulogize philosophy for the benefits which the
laborious efforts of its criticism have conferred on human reason-
even granting that its merit should turn out in the end to be only
negative--for on this point something more will be said in the next
section. But, I ask, do you require that that knowledge which concerns
all men, should transcend the common understanding, and should only
be revealed to you by philosophers? The very circumstance which has
called forth your censure, is the best confirmation of the correctness
of our previous assertions, since it discloses, what could not have
been foreseen, that Nature is not chargeable with any partial
distribution of her gifts in those matters which concern all men
without distinction and that, in respect to the essential ends of
human nature, we cannot advance further with the help of the highest
philosophy, than under the guidance which nature has vouchsafed to
the meanest understanding.

CHAPTER III. The Architectonic of Pure Reason.

By the term architectonic I mean the art of constructing a system.
Without systematic unity, our knowledge cannot become science; it will
be an aggregate, and not a system. Thus architectonic is the
doctrine of the scientific in cognition, and therefore necessarily
forms part of our methodology.

Reason cannot permit our knowledge to remain in an unconnected and
rhapsodistic state, but requires that the sum of our cognitions should
constitute a system. It is thus alone that they can advance the ends
of reason. By a system I mean the unity of various cognitions under
one idea. This idea is the conception--given by reason--of the form
of a whole, in so far as the conception determines a priori not only
the limits of its content, but the place which each of its parts is
to occupy. The scientific idea contains, therefore, the end and the
form of the whole which is in accordance with that end. The unity of
the end, to which all the parts of the system relate, and through
which all have a relation to each other, communicates unity to the
whole system, so that the absence of any part can be immediately
detected from our knowledge of the rest; and it determines a priori
the limits of the system, thus excluding all contingent or arbitrary
additions. The whole is thus an organism (articulatio), and not an
aggregate (coacervatio); it may grow from within (per
intussusceptionem), but it cannot increase by external additions
(per appositionem). It is, thus, like an animal body, the growth of
which does not add any limb, but, without changing their
proportions, makes each in its sphere stronger and more active.

We require, for the execution of the idea of a system, a schema,
that is, a content and an arrangement of parts determined a priori
by the principle which the aim of the system prescribes. A schema
which is not projected in accordance with an idea, that is, from the
standpoint of the highest aim of reason, but merely empirically, in
accordance with accidental aims and purposes (the number of which
cannot be predetermined), can give us nothing more than technical
unity. But the schema which is originated from an idea (in which
case reason presents us with aims a priori, and does not look for them
to experience), forms the basis of architectonical unity. A science,
in the proper acceptation of that term, cannot be formed
technically, that is, from observation of the similarity existing
between different objects, and the purely contingent use we make of
our knowledge in concreto with reference to all kinds of arbitrary
external aims; its constitution must be framed on architectonical
principles, that is, its parts must be shown to possess an essential
affinity, and be capable of being deduced from one supreme and
internal aim or end, which forms the condition of the possibility of
the scientific whole. The schema of a science must give a priori the
plan of it (monogramma), and the division of the whole into parts,
in conformity with the idea of the science; and it must also
distinguish this whole from all others, according to certain
understood principles.

No one will attempt to construct a science, unless he have some idea
to rest on as a proper basis. But, in the elaboration of the
science, he finds that the schema, nay, even the definition which he
at first gave of the science, rarely corresponds with his idea; for
this idea lies, like a germ, in our reason, its parts undeveloped
and hid even from microscopical observation. For this reason, we ought
to explain and define sciences, not according to the description which
the originator gives of them, but according to the idea which we
find based in reason itself, and which is suggested by the natural
unity of the parts of the science already accumulated. For it will
of ten be found that the originator of a science and even his latest
successors remain attached to an erroneous idea, which they cannot
render clear to themselves, and that they thus fail in determining
the true content, the articulation or systematic unity, and the limits
of their science.

It is unfortunate that, only after having occupied ourselves for a
long time in the collection of materials, under the guidance of an
idea which lies undeveloped in the mind, but not according to any
definite plan of arrangement--nay, only after we have spent much
time and labour in the technical disposition of our materials, does
it become possible to view the idea of a science in a clear light,
and to project, according to architectonical principles, a plan of
the whole, in accordance with the aims of reason. Systems seem, like
certain worms, to be formed by a kind of generatio aequivoca--by the
mere confluence of conceptions, and to gain completeness only with
the progress of time. But the schema or germ of all lies in reason;
and thus is not only every system organized according to its own idea,
but all are united into one grand system of human knowledge, of which
they form members. For this reason, it is possible to frame an
architectonic of all human cognition, the formation of which, at the
present time, considering the immense materials collected or to be
found in the ruins of old systems, would not indeed be very difficult.
Our purpose at present is merely to sketch the plan of the
architectonic of all cognition given by pure reason; and we begin from
the point where the main root of human knowledge divides into two,
one of which is reason. By reason I understand here the whole higher
faculty of cognition, the rational being placed in contradistinction
to the empirical.

If I make complete abstraction of the content of cognition,
objectively considered, all cognition is, from a subjective point of
view, either historical or rational. Historical cognition is
cognitio ex datis, rational, cognitio ex principiis. Whatever may be
the original source of a cognition, it is, in relation to the person
who possesses it, merely historical, if he knows only what has been
given him from another quarter, whether that knowledge was
communicated by direct experience or by instruction. Thus the Person
who has learned a system of philosophy--say the Wolfian--although he
has a perfect knowledge of all the principles, definitions, and
arguments in that philosophy, as well as of the divisions that have
been made of the system, possesses really no more than an historical
knowledge of the Wolfian system; he knows only what has been told him,
his judgements are only those which he has received from his teachers.
Dispute the validity of a definition, and he is completely at a loss
to find another. He has formed his mind on another's; but the
imitative faculty is not the productive. His knowledge has not been
drawn from reason; and although, objectively considered, it is
rational knowledge, subjectively, it is merely historical. He has
learned this or that philosophy and is merely a plaster cast of a
living man. Rational cognitions which are objective, that is, which
have their source in reason, can be so termed from a subjective
point of view, only when they have been drawn by the individual
himself from the sources of reason, that is, from principles; and it
is in this way alone that criticism, or even the rejection of what
has been already learned, can spring up in the mind.

All rational cognition is, again, based either on conceptions, or on
the construction of conceptions. The former is termed philosophical,
the latter mathematical. I have already shown the essential difference
of these two methods of cognition in the first chapter. A cognition
may be objectively philosophical and subjectively historical--as is
the case with the majority of scholars and those who cannot look
beyond the limits of their system, and who remain in a state of
pupilage all their lives. But it is remarkable that mathematical
knowledge, when committed to memory, is valid, from the subjective
point of view, as rational knowledge also, and that the same
distinction cannot be drawn here as in the case of philosophical
cognition. The reason is that the only way of arriving at this
knowledge is through the essential principles of reason, and thus it
is always certain and indisputable; because reason is employed in
concreto--but at the same time a priori--that is, in pure and,
therefore, infallible intuition; and thus all causes of illusion and
error are excluded. Of all the a priori sciences of reason, therefore,
mathematics alone can be learned. Philosophy--unless it be in an
historical manner--cannot be learned; we can at most learn to

Philosophy is the system of all philosophical cognition. We must use
this term in an objective sense, if we understand by it the archetype
of all attempts at philosophizing, and the standard by which all
subjective philosophies are to be judged. In this sense, philosophy is
merely the idea of a possible science, which does not exist in
concreto, but to which we endeavour in various ways to approximate,
until we have discovered the right path to pursue--a path overgrown by
the errors and illusions of sense--and the image we have hitherto tried
in vain to shape has become a perfect copy of the great prototype.
Until that time, we cannot learn philosophy--it does not exist; if it
does, where is it, who possesses it, and how shall we know it? We can
only learn to philosophize; in other words, we can only exercise our
powers of reasoning in accordance with general principles, retaining at
the same time, the right of investigating the sources of these
principles, of testing, and even of rejecting them.

Until then, our conception of philosophy is only a scholastic
conception--a conception, that is, of a system of cognition which we
are trying to elaborate into a science; all that we at present know
being the systematic unity of this cognition, and consequently the
logical completeness of the cognition for the desired end. But there
is also a cosmical conception (conceptus cosmicus) of philosophy,
which has always formed the true basis of this term, especially when
philosophy was personified and presented to us in the ideal of a
philosopher. In this view philosophy is the science of the relation
of all cognition to the ultimate and essential aims of human reason
(teleologia rationis humanae), and the philosopher is not merely an
artist--who occupies himself with conceptions--but a lawgiver,
legislating for human reason. In this sense of the word, it would be
in the highest degree arrogant to assume the title of philosopher,
and to pretend that we had reached the perfection of the prototype
which lies in the idea alone.

The mathematician, the natural philosopher, and the logician--how
far soever the first may have advanced in rational, and the two latter
in philosophical knowledge--are merely artists, engaged in the
arrangement and formation of conceptions; they cannot be termed
philosophers. Above them all, there is the ideal teacher, who
employs them as instruments for the advancement of the essential
aims of human reason. Him alone can we call philosopher; but he
nowhere exists. But the idea of his legislative power resides in the
mind of every man, and it alone teaches us what kind of systematic
unity philosophy demands in view of the ultimate aims of reason.
This idea is, therefore, a cosmical conception.*

[*Footnote: By a cosmical conception, I mean one in which all men
necessarily take an interest; the aim of a science must accordingly
be determined according to scholastic conceptions, if it is regarded
merely as a means to certain arbitrarily proposed ends.]

In view of the complete systematic unity of reason, there can only
be one ultimate end of all the operations of the mind. To this all
other aims are subordinate, and nothing more than means for its
attainment. This ultimate end is the destination of man, and the
philosophy which relates to it is termed moral philosophy. The
superior position occupied by moral philosophy, above all other
spheres for the operations of reason, sufficiently indicates the
reason why the ancients always included the idea--and in an especial
manner--of moralist in that of philosopher. Even at the present day,
we call a man who appears to have the power of self-government, even
although his knowledge may be very limited, by the name of

The legislation of human reason, or philosophy, has two objects-
nature and freedom--and thus contains not only the laws of nature,
but also those of ethics, at first in two separate systems, which,
finally, merge into one grand philosophical system of cognition. The
philosophy of nature relates to that which is, that of ethics to
that which ought to be.

But all philosophy is either cognition on the basis of pure
reason, or the cognition of reason on the basis of empirical
principles. The former is termed pure, the latter empirical

The philosophy of pure reason is either propaedeutic, that is, an
inquiry into the powers of reason in regard to pure a priori
cognition, and is termed critical philosophy; or it is, secondly,
the system of pure reason--a science containing the systematic
presentation of the whole body of philosophical knowledge, true as
well as illusory, given by pure reason--and is called metaphysic. This
name may, however, be also given to the whole system of pure
philosophy, critical philosophy included, and may designate the
investigation into the sources or possibility of a priori cognition,
as well as the presentation of the a priori cognitions which form a
system of pure philosophy--excluding, at the same time, all
empirical and mathematical elements.

Metaphysic is divided into that of the speculative and that of the
practical use of pure reason, and is, accordingly, either the
metaphysic of nature, or the metaphysic of ethics. The former contains
all the pure rational principles--based upon conceptions alone (and
thus excluding mathematics)--of all theoretical cognition; the latter,
the principles which determine and necessitate a priori all action.
Now moral philosophy alone contains a code of laws--for the regulation
of our actions--which are deduced from principles entirely a priori.
Hence the metaphysic of ethics is the only pure moral philosophy, as
it is not based upon anthropological or other empirical
considerations. The metaphysic of speculative reason is what is
commonly called metaphysic in the more limited sense. But as pure
moral philosophy properly forms a part of this system of cognition,
we must allow it to retain the name of metaphysic, although it is not
requisite that we should insist on so terming it in our present

It is of the highest importance to separate those cognitions which
differ from others both in kind and in origin, and to take great
care that they are not confounded with those with which they are
generally found connected. What the chemist does in the analysis of
substances, what the mathematician in pure mathematics, is, in a still
higher degree, the duty of the philosopher, that the value of each
different kind of cognition, and the part it takes in the operations
of the mind, may be clearly defined. Human reason has never wanted
a metaphysic of some kind, since it attained the power of thought,
or rather of reflection; but it has never been able to keep this sphere
of thought and cognition pure from all admixture of foreign
elements. The idea of a science of this kind is as old as
speculation itself; and what mind does not speculate--either in the
scholastic or in the popular fashion? At the same time, it must be
admitted that even thinkers by profession have been unable clearly
to explain the distinction between the two elements of our
cognition--the one completely a priori, the other a posteriori; and
hence the proper definition of a peculiar kind of cognition, and
with it the just idea of a science which has so long and so deeply
engaged the attention of the human mind, has never been established.
When it was said: "Metaphysic is the science of the first principles
of human cognition," this definition did not signalize a peculiarity
in kind, but only a difference in degree; these first principles
were thus declared to be more general than others, but no criterion
of distinction from empirical principles was given. Of these some are
more general, and therefore higher, than others; and--as we cannot
distinguish what is completely a priori from that which is known to
be a posteriori--where shall we draw the line which is to separate
the higher and so-called first principles, from the lower and
subordinate principles of cognition? What would be said if we were
asked to be satisfied with a division of the epochs of the world
into the earlier centuries and those following them? "Does the
fifth, or the tenth century belong to the earlier centuries?" it would
be asked. In the same way I ask: Does the conception of extension
belong to metaphysics? You answer, "Yes." Well, that of body too?
"Yes." And that of a fluid body? You stop, you are unprepared to admit
this; for if you do, everything will belong to metaphysics. From
this it is evident that the mere degree of subordination--of the
particular to the general--cannot determine the limits of a science;
and that, in the present case, we must expect to find a difference
in the conceptions of metaphysics both in kind and in origin. The
fundamental idea of metaphysics was obscured on another side by the
fact that this kind of a priori cognition showed a certain
similarity in character with the science of mathematics. Both have
the property in common of possessing an a priori origin; but, in the
one, our knowledge is based upon conceptions, in the other, on the
construction of conceptions. Thus a decided dissimilarity between
philosophical and mathematical cognition comes out--a dissimilarity
which was always felt, but which could not be made distinct for want
of an insight into the criteria of the difference. And thus it
happened that, as philosophers themselves failed in the proper
development of the idea of their science, the elaboration of the
science could not proceed with a definite aim, or under trustworthy
guidance. Thus, too, philosophers, ignorant of the path they ought
to pursue and always disputing with each other regarding the
discoveries which each asserted he had made, brought their science
into disrepute with the rest of the world, and finally, even among

All pure a priori cognition forms, therefore, in view of the
peculiar faculty which originates it, a peculiar and distinct unity;
and metaphysic is the term applied to the philosophy which attempts
to represent that cognition in this systematic unity. The speculative
part of metaphysic, which has especially appropriated this
appellation--that which we have called the metaphysic of nature--and
which considers everything, as it is (not as it ought to be), by means
of a priori conceptions, is divided in the following manner.

Metaphysic, in the more limited acceptation of the term, consists of
two parts--transcendental philosophy and the physiology of pure
reason. The former presents the system of all the conceptions and
principles belonging to the understanding and the reason, and which
relate to objects in general, but not to any particular given
objects (Ontologia); the latter has nature for its subject-matter,
that is, the sum of given objects--whether given to the senses, or,
if we will, to some other kind of intuition--and is accordingly
physiology, although only rationalis. But the use of the faculty of
reason in this rational mode of regarding nature is either physical
or hyperphysical, or, more properly speaking, immanent or transcendent.
The former relates to nature, in so far as our knowledge regarding
it may be applied in experience (in concreto); the latter to that
connection of the objects of experience, which transcends all
experience. Transcendent physiology has, again, an internal and an
external connection with its object, both, however, transcending
possible experience; the former is the physiology of nature as a
whole, or transcendental cognition of the world, the latter of the
connection of the whole of nature with a being above nature, or
transcendental cognition of God.

Immanent physiology, on the contrary, considers nature as the sum of
all sensuous objects, consequently, as it is presented to us--but
still according to a priori conditions, for it is under these alone
that nature can be presented to our minds at all. The objects of
immanent physiology are of two kinds: 1. Those of the external senses,
or corporeal nature; 2. The object of the internal sense, the soul,
or, in accordance with our fundamental conceptions of it, thinking
nature. The metaphysics of corporeal nature is called physics; but,
as it must contain only the principles of an a priori cognition of
nature, we must term it rational physics. The metaphysics of
thinking nature is called psychology, and for the same reason is to
be regarded as merely the rational cognition of the soul.

Thus the whole system of metaphysics consists of four principal
parts: 1. Ontology; 2. Rational Physiology; 3. Rational cosmology;
and 4. Rational theology. The second part--that of the rational doctrine
of nature--may be subdivided into two, physica rationalis* and
psychologia rationalis.

[*Footnote: It must not be supposed that I mean by this appellation
what is generally called physica general is, and which is rather
mathematics than a philosophy of nature. For the metaphysic of nature
is completely different from mathematics, nor is it so rich in results,
although it is of great importance as a critical test of the
application of pure understanding-cognition to nature. For want of
its guidance, even mathematicians, adopting certain common notions-
which are, in fact, metaphysical--have unconsciously crowded their
theories of nature with hypotheses, the fallacy of which becomes
evident upon the application of the principles of this metaphysic,
without detriment, however, to the employment of mathematics in this
sphere of cognition.]

The fundamental idea of a philosophy of pure reason of necessity
dictates this division; it is, therefore, architectonical--in
accordance with the highest aims of reason, and not merely
technical, or according to certain accidentally-observed
similarities existing between the different parts of the whole
science. For this reason, also, is the division immutable and of
legislative authority. But the reader may observe in it a few points
to which he ought to demur, and which may weaken his conviction of
its truth and legitimacy.

In the first place, how can I desire an a priori cognition or
metaphysic of objects, in so far as they are given a posteriori? and
how is it possible to cognize the nature of things according to a
priori principles, and to attain to a rational physiology? The
answer is this. We take from experience nothing more than is requisite
to present us with an object (in general) of the external or of the
internal sense; in the former case, by the mere conception of matter
(impenetrable and inanimate extension), in the latter, by the
conception of a thinking being--given in the internal empirical
representation, I think. As to the rest, we must not employ in our
metaphysic of these objects any empirical principles (which add to
the content of our conceptions by means of experience), for the purpose
of forming by their help any judgements respecting these objects.

Secondly, what place shall we assign to empirical psychology,
which has always been considered a part of metaphysics, and from which
in our time such important philosophical results have been expected,
after the hope of constructing an a priori system of knowledge had
been abandoned? I answer: It must be placed by the side of empirical
physics or physics proper; that is, must be regarded as forming a part
of applied philosophy, the a priori principles of which are
contained in pure philosophy, which is therefore connected, although
it must not be confounded, with psychology. Empirical psychology
must therefore be banished from the sphere of metaphysics, and is
indeed excluded by the very idea of that science. In conformity,
however, with scholastic usage, we must permit it to occupy a place
in metaphysics--but only as an appendix to it. We adopt this course
from motives of economy; as psychology is not as yet full enough to
occupy our attention as an independent study, while it is, at the same
time, of too great importance to be entirely excluded or placed
where it has still less affinity than it has with the subject of
metaphysics. It is a stranger who has been long a guest; and we make
it welcome to stay, until it can take up a more suitable abode in a
complete system of anthropology--the pendant to empirical physics.

The above is the general idea of metaphysics, which, as more was
expected from it than could be looked for with justice, and as these
pleasant expectations were unfortunately never realized, fell into
general disrepute. Our Critique must have fully convinced the reader
that, although metaphysics cannot form the foundation of religion,
it must always be one of its most important bulwarks, and that human
reason, which naturally pursues a dialectical course, cannot do
without this science, which checks its tendencies towards dialectic
and, by elevating reason to a scientific and clear self-knowledge,
prevents the ravages which a lawless speculative reason would
infallibly commit in the sphere of morals as well as in that of
religion. We may be sure, therefore, whatever contempt may be thrown
upon metaphysics by those who judge a science not by its own nature,
but according to the accidental effects it may have produced, that
it can never be completely abandoned, that we must always return to
it as to a beloved one who has been for a time estranged, because the
questions with which it is engaged relate to the highest aims of
humanity, and reason must always labour either to attain to settled
views in regard to these, or to destroy those which others have
already established.

Metaphysic, therefore--that of nature, as well as that of ethics,
but in an especial manner the criticism which forms the propaedeutic
to all the operations of reason--forms properly that department of
knowledge which may be termed, in the truest sense of the word,
philosophy. The path which it pursues is that of science, which,
when it has once been discovered, is never lost, and never misleads.
Mathematics, natural science, the common experience of men, have a
high value as means, for the most part, to accidental ends--but at
last also, to those which are necessary and essential to the existence
of humanity. But to guide them to this high goal, they require the
aid of rational cognition on the basis of pure conceptions, which,
be it termed as it may, is properly nothing but metaphysics.

For the same reason, metaphysics forms likewise the completion of
the culture of human reason. In this respect, it is indispensable,
setting aside altogether the influence which it exerts as a science.
For its subject-matter is the elements and highest maxims of reason,
which form the basis of the possibility of some sciences and of the
use of all. That, as a purely speculative science, it is more useful
in preventing error than in the extension of knowledge, does not
detract from its value; on the contrary, the supreme office of
censor which it occupies assures to it the highest authority and
importance. This office it administers for the purpose of securing
order, harmony, and well-being to science, and of directing its
noble and fruitful labours to the highest possible aim--the
happiness of all mankind.

CHAPTER IV. The History of Pure Reason.

This title is placed here merely for the purpose of designating a
division of the system of pure reason of which I do not intend to
treat at present. I shall content myself with casting a cursory
glance, from a purely transcendental point of view--that of the nature
of pure reason--on the labours of philosophers up to the present time.
They have aimed at erecting an edifice of philosophy; but to my eye
this edifice appears to be in a very ruinous condition.

It is very remarkable, although naturally it could not have been
otherwise, that, in the infancy of philosophy, the study of the nature
of God and the constitution of a future world formed the commencement,
rather than the conclusion, as we should have it, of the speculative
efforts of the human mind. However rude the religious conceptions
generated by the remains of the old manners and customs of a less
cultivated time, the intelligent classes were not thereby prevented
from devoting themselves to free inquiry into the existence and nature
of God; and they easily saw that there could be no surer way of
pleasing the invisible ruler of the world, and of attaining to
happiness in another world at least, than a good and honest course
of life in this. Thus theology and morals formed the two chief
motives, or rather the points of attraction in all abstract inquiries.
But it was the former that especially occupied the attention of
speculative reason, and which afterwards became so celebrated under
the name of metaphysics.

I shall not at present indicate the periods of time at which the
greatest changes in metaphysics took place, but shall merely give a
hasty sketch of the different ideas which occasioned the most
important revolutions in this sphere of thought. There are three
different ends in relation to which these revolutions have taken

1. In relation to the object of the cognition of reason,
philosophers may be divided into sensualists and intellectualists.
Epicurus may be regarded as the head of the former, Plato of the
latter. The distinction here signalized, subtle as it is, dates from
the earliest times, and was long maintained. The former asserted
that reality resides in sensuous objects alone, and that everything
else is merely imaginary; the latter, that the senses are the
parents of illusion and that truth is to be found in the understanding
alone. The former did not deny to the conceptions of the understanding
a certain kind of reality; but with them it was merely logical, with
the others it was mystical. The former admitted intellectual
conceptions, but declared that sensuous objects alone possessed real
existence. The latter maintained that all real objects were
intelligible, and believed that the pure understanding possessed a
faculty of intuition apart from sense, which, in their opinion, served
only to confuse the ideas of the understanding.

2. In relation to the origin of the pure cognitions of reason, we
find one school maintaining that they are derived entirely from
experience, and another that they have their origin in reason alone.
Aristotle may be regarded as the bead of the empiricists, and Plato
of the noologists. Locke, the follower of Aristotle in modern times,
and Leibnitz of Plato (although he cannot be said to have imitated
him in his mysticism), have not been able to bring this question to
a settled conclusion. The procedure of Epicurus in his sensual system,
in which he always restricted his conclusions to the sphere of
experience, was much more consequent than that of Aristotle and Locke.
The latter especially, after having derived all the conceptions and
principles of the mind from experience, goes so far, in the employment
of these conceptions and principles, as to maintain that we can
prove the existence of God and the existence of God and the
immortality of them objects lying beyond the soul--both of them of
possible experience--with the same force of demonstration as any
mathematical proposition.

3. In relation to method. Method is procedure according to
principles. We may divide the methods at present employed in the field
of inquiry into the naturalistic and the scientific. The naturalist
of pure reason lays it down as his principle that common reason,
without the aid of science--which he calls sound reason, or common
sense--can give a more satisfactory answer to the most important
questions of metaphysics than speculation is able to do. He must
maintain, therefore, that we can determine the content and
circumference of the moon more certainly by the naked eye, than by
the aid of mathematical reasoning. But this system is mere misology
reduced to principles; and, what is the most absurd thing in this
doctrine, the neglect of all scientific means is paraded as a peculiar
method of extending our cognition. As regards those who are
naturalists because they know no better, they are certainly not to
be blamed. They follow common sense, without parading their
ignorance as a method which is to teach us the wonderful secret, how
we are to find the truth which lies at the bottom of the well of

Quod sapio satis est mihi, non ego curo Esse quod
Arcesilas aerumnosique Solones. PERSIUS
-- Satirae, iii. 78-79.

is their motto, under which they may lead a pleasant and praiseworthy
life, without troubling themselves with science or troubling science
with them.

As regards those who wish to pursue a scientific method, they have
now the choice of following either the dogmatical or the sceptical,
while they are bound never to desert the systematic mode of procedure.
When I mention, in relation to the former, the celebrated Wolf, and
as regards the latter, David Hume, I may leave, in accordance with
my present intention, all others unnamed. The critical path alone is
still open. If my reader has been kind and patient enough to accompany
me on this hitherto untravelled route, he can now judge whether, if
he and others will contribute their exertions towards making this
narrow footpath a high road of thought, that which many centuries have
failed to accomplish may not be executed before the close of the
present--namely, to bring Reason to perfect contentment in regard to
that which has always, but without permanent results, occupied her
powers and engaged her ardent desire for knowledge.

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