TRANSITION FROM THE METAPHYSIC OF MORALS TO THE CRITIQUE OF PURE
PRACTICAL REASOH
The Concept of Freedom is the Key that explains the Autonomy of the
Will
The WILL is a kind of causality belonging to living beings in so far
as they are rational, and FREEDOM would be this property of such
causality that it can be efficient, independently on foreign causes
DETERMINING it; just as PHYSICAL NECESSITY is the property that the
causality of all irrational beings has of being determined to
activity by the influence of foreign causes.
The preceding definition of freedom is NEGATIVE, and therefore
unfruitful for the discovery of its essence; but it leads to a
POSITIVE conception which is so much the more full and fruitful
Since the conception of causality involves that of laws, according
to which, by something that we call cause, something else, namely,
the effect, must be produced [laid down]; [Footnote: (Gesetzt.-There
is in the original a play on the etymology of Gesetz, which does not
admit of reproduction in English. It must be confessed that without
it the statement is not self-evident.)] hence, although freedom is
not a property of the will depending on physical laws, yet it is not
for that reason lawless; on the contrary it must be a causality
acting according to immutable laws, but of a peculiar kind;
otherwise a free will would be an absurdity. Physical necessity is a
heteronomy of the efficient causes, for every effect is possible
only according to this law, that something else determines the
efficient cause to exert its causality. What else then can freedom
of the will be but autonomy, that is the property of the will to be
a law to itself? But the proposition: The will is in every action a
law to itself, only expresses the principle, to act on no other
maxim than that which can also have as an object itself as a
universal law. Now this is precisely the formula of the categorical
imperative and is the principle of morality, so that a free will and
a will subject to moral laws are one and the same.
On the hypothesis then of freedom of the will, morality together
with its principle follows from it by mere analysis of the
conception. However the latter is still a synthetic proposition;
viz., an absolutely good will is that whose maxim can always include
itself regarded as a universal law; for this property of its maxim
can never be discovered by analysing the conception of an absolutely
good will. Now such synthetic propositions are only possible in this
way: that the two cognitions are connected together by their union
with a third in which they are both to be found. The POSITIVE
concept of freedom furnishes this third cognition, which cannot, as
with physical causes, be the nature of the sensible world (in the
concept of which we find conjoined the concept of something in
relation as cause to SOMETHING ELSE as effect). We cannot now at
once show what this third is to which freedom points us, and of
which we have an idea a priori, nor can we make intelligible how the
concept of freedom is shown to be legitimate from principles of pure
practical reason, and with it the possibility of a categorical
imperative; but some further preparation is required.
Freedom must be presupposed as a Property of the Will of all
Rational Beings
It is not enough to predicate freedom of our own will, from whatever
reason, if we have not sufficient grounds for predicating the same
of all rational beings. For as morality serves as a law for us only
because we are RATIONAL BEINGS, it must also hold for all rational
beings; and as it must be deduced simply from the property of
freedom, it must be shown that freedom also is a property of all
rational beings. It is not enough then to prove it from certain
supposed experiences of human nature (which indeed is quite
impossible, and it can only be shown a priori), but we must show
that it belongs to the activity of all rational beings endowed with
a will. Now I say every being that cannot act except UNDER THE IDEA
OF FREEDOM is just for that reason in a practical point of view
really free, that is to say, all laws which are inseparably
connected with freedom have the same force for him as if his will
had been shown to be free in itself by a proof theoretically
conclusive. [Footnote: I adopt this method of assuming freedom
merely AS AN IDEA which rational beings suppose in their actions, in
order to avoid the necessity of proving it in its theoretical aspect
also. The former is sufficient for my purpose; for even though the
speculative proof should not be made out, yet a being that cannot
act except with the idea of freedom is bound by the same laws that
would oblige a being who was actually free. Thus we can escape here
from the onus which presses on the theory. (Compare Butler's
treatment of the question of liberty in his "Analogy," part I., ch.
vi.)] Now I affirm that we must attribute to every rational being
which has a will that it has also the idea of freedom and acts
entirely under this idea. For in such a being we conceive a reason
that is practical, that is, has causality in reference to its
objects. Now we cannot possibly conceive a reason consciously
receiving a bias from any other quarter with respect to its
judgments, for then the subject would ascribe the determination of
its judgment not to its own reason, but to an impulse. It must
regard itself as the author of its principles independent on foreign
influences. Consequently as practical reason or as the will of a
rational being it must regard itself as free, that is to say, the
will of such a being cannot be a will of its own except under the
idea of freedom. This idea must therefore in a practical point of
view be ascribed to every rational being.