Kant’s argument for the formula of ends
The question is therefore this: is it a necessary law for all rational beings always to appraise their actions in accordance
with such maxims as they themselves could will to serve as universal laws? If there is such a law, then it must already be
connected (completely a priori) with the concept of the will of a rational being as such. But in order to discover this
connection we must, however reluctantly, step forth, namely into metaphysics, although into a domain of it that is
distinct from speculative philosophy,1 namely into metaphysics of morals. [427] In a practical philosophy, where we
have to do not with assuming grounds for what happens but rather laws for what ought to happen even if it never does,
that is, objective practical laws, we do not need to undertake an investigation into the grounds on account of which
something pleases or displeases; how the satisfaction of mere sensation differs from taste, and whether the latter differs
from a general satisfaction of reason; upon what the feeling of pleasure or displeasure rests, and how from it desires and
inclinations arise, and from them, with the cooperation of reason, maxims; for all that belongs to an empirical doctrine of
the soul,2 which would constitute the second part of the doctrine of nature when this is regarded as philosophy of nature
insofar as it is based on empirical laws. Here, however, it is a question of objective practical laws and hence of the
relation of a will to itself insofar as it determines itself only by reason; for then everything that has reference to the
empirical falls away of itself, since if reason entirely by itself determines conduct (and the possibility of this is just what
we want now to investigate), it must necessarily do so a priori.3
The will is thought as a capacity to determine itself to acting in conformity with the representation of certain laws. And
such a capacity can be found only in rational beings. Now, what serves the will as the objective ground of its selfdetermination is an end, and this, if it is given by reason alone, must hold equally for all rational beings. What, on the
other hand, contains merely the ground of the possibility of an action the effect of which is an end is called a means. The
subjective ground of desire is an incentive; the objective ground of volition is a motive; hence the distinction between
subjective ends, which rest on incentives, and objective ends, which depend on motives, which hold for every rational
being.4 Practical principles are formal if they abstract from all subjective ends, whereas they are material if they have
put these, and consequently certain incentives, at their basis.5 The ends that a rational being proposes at his discretion as
effects of his actions (material ends) are all only relative; for only their mere relation to a specially constituted faculty of
desire on the part of the subject gives them their worth,6 which can therefore furnish no universal principles, no
principles valid and necessary [428] for all rational beings and also for every volition, that is, no practical laws.7 Hence
all these relative ends are only the ground of hypothetical imperatives. But suppose there were something the existence
of which in itself has an absolute worth, something which as an end in itself8 could be a ground of determinate laws; then
in it, and in it alone, would lie the ground of a possible categorical imperative, that is, of a practical law.
Now I say that the human being and in general every rational being9 exists as an end in itself, not merely as a means to
be used by this or that will at its discretion; instead he must in all his actions, whether directed to himself or also to other
rational beings, always be regarded at the same time as an end.10 All objects of the inclinations have only a conditional
worth; for, if there were not inclinations and the needs based on them, their object would be without worth. But the
inclinations themselves, as sources of needs, are so far from having an absolute worth, so as to make one wish to have
them, that it must instead be the universal wish of every rational being to be altogether free from them. Thus the worth
of any object to be acquired by our action is always conditional. Beings the existence of which rests not on our will but
on nature, if they are beings without reason, still have only a relative worth, as means, and are therefore called things11
whereas rational beings are called persons because their nature already marks them out as an end in itself, that is, as
something that may not be used merely as a means, and hence so far limits all choice (and is an object of respect). These,
therefore, are not merely subjective ends, the existence of which as an effect of our action has a worth for us, but rather
objective ends, that is, beings12 the existence of which is in itself an end, and indeed one such that no other end, to which
they would serve merely as means, can be put in its place, since without it nothing of absolute worth would be found
anywhere; but if all worth were conditional and therefore contingent, then no supreme practical principle for reason
could be found anywhere.
If, then, there is to be a supreme practical principle and, with respect to the human will, a categorical imperative, it must
be one such that, from the representation of what is necessarily an end for everyone because it is an end in itself, it
constitutes an objective [429] principle of the will and thus can serve as a universal practical law.13 The ground of this
principle is: rational nature14 exists as an end in itself. The human being necessarily represents his own existence in this
way; so far it is thus a subjective principle of human actions. 15 But 16every other rational being also represents his
existence in this way consequent on just the same rational ground that also holds for me;* thus it is at the same time an
objective principle from which, as a supreme practical ground, it must be possible to derive all laws of the will. The
practical imperative will therefore be the following: So act that you use humanity, whether in your own person or in the
person of any other, always at the same time as an end, never merely as a means. We shall see whether this can be
carried out.
*Here I put forward this proposition as a postulate. The grounds for it will be found in the last Section.
(Source: Kant, Groundwork of the Metaphysics of Morals, ed. Mary Gregor, CUP, 1997, pp.35-38)
© Cambridge University Press, 1997
Notes
1
For Kant speculative philosophy has to do with the nature of reality, as opposed to practical philosophy which has
to do with how we rationally ought to act.
2
I.e. to empirical psychology.
3
I.e. without basing itself on any empirically given desires.
4
‘End’ means the aim or purpose that governs an action. Subjective ends are ends based on the particular
individual’s desires. An objective end would be an end that one has to set oneself simply in virtue of being a
rational actor, regardless of one’s own particular desires.
5
So a formal practical principle is the same thing as a categorical imperative and a material practical principle is
the same thing as a hypothetical imperative.
6
Material ends are the same as subjective ends (above). They have some worth (i.e. value) for the actor only
because attaining the end will fulfil one of the actor’s desires.
7
Practical laws are the same thing as formal practical principles, i.e. categorical imperatives (above). They are
universal because they apply to all rational actors.
8
Just as subjective ends have relative worth, i.e. have a worth only on condition that the actor has desires that will
be fulfilled by attaining the end, so an objective end would have absolute worth, i.e. a worth independent of the
actor’s desires. It would be an end in itself rather than an end grounded on the actor’s desires.
9
All humans are rational beings, and often Kant uses the terms ‘human’ and ‘rational’ interchangeably, but here he
Kant allows for the possibility of non-human rational beings.
10
At 437 Kant says that:
since abstraction must be made altogether from every end to be effected … the end must here be thought not as
an end to be effected but as a self-sufficient [selbständiger] end, and hence thought only negatively, that is, as
that which must never be acted against …
So he distinguishes two ways that something can be the end that governs an action: (1) positively, in that it is
something that the action tries to bring about (this is how we normally think of the aim or purpose of an action),
and (2) negatively, in that it is something that the action tries to avoid destroying or obstructing. When he says that
humans must be treated as ends he means the second kind of end. His two examples of treating other humans as
ends at 429-30 are not making promises to them which you intend to break, and helping them to realise their own
(positive) ends
11
Sache. This has the technical sense of something that does not have free choice.
12
Dinge. This is a general word for a thing or entity.
13
The two sentences that follow (underlined) are the heart of Kant’s argument.
14
At 437 Kant says ‘Rational nature is distinguished from the rest of nature by this, that it sets itself an end.’ So it
looks as if a ‘rational being’, or an instance of ‘rational nature’, is a physical entity that has the capacity to adopt
ends, i.e. to act deliberately in the light of some end.
15
A ‘subjective principle’ means any principle on which someone does as a matter of fact act. At 421 he says:
A maxim is the subjective principle of acting, and must be distinguished from the objective principle, namely
the practical law. The former contains the practical rule determined by reason conformably with the conditions
of the subject (often his ignorance or also his inclination), and is therefore the principle in accordance with
which the subject acts; but the law is the objective principle valid for every rational being, and the principle in
accordance with which he ought to act, i.e. an imperative. (cf a shorter version of the same definition at 401)
Here Kant speaks of a subjective principle to which every human being ‘necessarily’ conforms. The idea must be
that as a human and so rational being, you are a being that adopts ends, and you cannot adopt any other end at all
unless you simultaneously adopt your own existence as a rational being as a (negative) end. You must be an end to
yourself to be able to adopt any other end.
Andrew Chitty
20 Jan 2006