Kant's Critique of Judgement

by Immanuel Kant

This principle, which is at the same time a definition, is as follows: An organised product of nature is one in which every part is reciprocally purpose, [end] and means. In it nothing is vain, without purpose, or to be ascribed to a blind mechanism of nature.

This principle, as regards its occasion, is doubtless derived from experience, viz. from that methodised experience called observation; but on account of the universality and necessity which it ascribes to such purposiveness it cannot rest solely on empirical grounds, but must have at its basis an a priori principle, although it be merely regulative and these purposes lie only in the idea of the judging [subject] and not in an effective cause. We may therefore describe the aforesaid principle as a maxim for judging of the internal purposiveness of organised beings.

It is an acknowledged fact that the dissectors of plants and animals, in order to investigate their structure and to find out the reasons, why and for what end such parts, such a disposition and combination of parts, and just such an internal form have been given them, assume as indisputably necessary the maxim that nothing in such a creature is vain; just as they lay down as the fundamental proposition of the universal science of nature, that nothing happens by chance. In fact, they can as little free themselves from this teleological proposition as from the universal physical proposition; for as without the latter we should have no experience at all, so without the former we should have no guiding thread for the observation of a species of natural things which we have thought teleologically under the concept of natural purposes.

Now this concept brings the Reason into a quite different order of things from that of a mere mechanism of nature, which is no longer satisfying here. An Idea is to be the ground of the possibility of the natural product. But because this is an absolute unity of representation, instead of the material being a plurality of things that can supply by itself no definite unity of composition,—if that unity of the Idea is to serve at all as the a priori ground of determination of a natural law of the causality of such a form of composition,—the purpose of nature must be extended to everything included in its product. For if we once refer action of this sort on the whole to any supersensible ground of determination beyond the blind mechanism of nature, we must judge of it altogether according to this principle; and we have then no reason to regard the form of such a thing as partly dependent on mechanism—for by such mixing up of disparate principles no certain rule of judging would be left.

For example, it may be that in an animal body many parts can be conceived as concretions according to mere mechanical laws (as the hide, the bones, the hair). And yet the cause which brings together the required matter, modifies it, forms it, and puts it in its appropriate place, must always be judged of teleologically; so that here everything must be considered as organised, and everything again in a certain relation to the thing itself is an organ.

§ 67. Of the principle of the teleological judging of nature in general as a system of purposes

We have already said above that the external purposiveness of natural things affords no sufficient warrant for using them as purposes of nature in order to explain their presence, and for regarding their contingently purposive effects as the grounds of their presence according to the principle of final causes. Thus we cannot take for natural purposes, rivers because they promote intercourse among inland peoples, mountains because they contain the sources of the rivers and for their maintenance in rainless seasons have a store of snow, or the slope of the land which carries away the water and leaves the country dry; because although this shape of the earth’s surface be very necessary for the origin and maintenance of the vegetable and animal kingdoms, it has nothing in itself for the possibility of which we are forced to assume a causality according to purposes. The same is true of plants which man uses for his needs or his pleasures; of beasts, the camel, the ox, the horse, dog, etc., which are indispensable to him as well for food as because they are used in his service in many different ways. In the case of things which we have no reason for regarding in themselves as purposes, such external relation can only be hypothetically judged as purposive.

To judge of a thing as a natural purpose on account of its internal form is something very different from taking the existence of that thing to be a purpose of nature. For the latter assertion we require not merely the concept of a possible purpose, but the knowledge of the final purpose (scopus) of nature. But this requires a reference of such knowledge to something supersensible far transcending all our teleological knowledge of nature, for the purpose of [the existence of][109] nature must itself be sought beyond nature. The internal form of a mere blade of grass is sufficient to show that for our human faculty of judgement its origin is possible only according to the rule of purposes. But if we change our point of view and look to the use which other natural beings make of it, abandon the consideration of its internal organisation and only look to its externally purposive references, we shall arrive at no categorical purpose; all this purposive reference rests on an ever more distant condition, which, as unconditioned (the presence of a thing as final purpose), lies quite outside the physico-teleological view of the world. For example, grass is needful for the ox, which again is needful for man as a means of existence, but then we do not see why it is necessary that men should exist (a question this, which we shall not find so easy to answer if we sometimes cast our thoughts on the New Hollanders or the inhabitants of Tierra del Fuego). So conceived, the thing is not even a natural purpose, for neither it (nor its whole genus) is to be regarded as a natural product.

Hence it is only so far as matter is organised that it necessarily carries with it the concept of a natural purpose, because this its specific form is at the same time a product of nature. But this concept leads necessarily to the Idea of collective nature as a system in accordance with the rule of purposes, to which Idea all the mechanism of nature must be subordinated according to principles of Reason (at least in order to investigate natural phenomena therein). The principle of Reason belongs to it only as a subjective principle or a maxim: viz. everything in the World is some way good for something; nothing is vain in it. By the example that nature gives us in its organic products we are justified, nay called upon, to expect of it and of its laws nothing that is not purposive on the whole.

It is plain that this is not a principle for the determinant but only for the reflective Judgement; that it is regulative and not constitutive; and that we derive from it a clue by which we consider natural things in reference to an already given ground of determination according to a new law-abiding order; and extend our natural science according to a different principle, viz. that of final causes, but yet without prejudice to the principle of mechanical causality. Furthermore, it is in no wise thus decided, whether anything of which we judge by this principle, is a designed purpose of nature; whether the grass is for the ox or the sheep, or whether these and the other things of nature are here for men. It is well also from this side to consider the things which are unpleasant to us and are contrary to purpose in particular references. Thus, for example, we can say: The vermin that torment men in their clothes, their hair, or their beds, may be, according to a wise appointment of nature, a motive to cleanliness which is in itself an important means for the preservation of health. Or again the mosquitoes and other stinging insects that make the wildernesses of America so oppressive to the savages, may be so many goads to activity for these primitive men, [inducing them] to drain the marshes and bring light into the forests which intercept every breath of air, and in this way, as well as by cultivating the soil, to make their habitations more healthy. The same thing, which appears to men contradictory to nature in its inner organisation, if viewed in this light gives an entertaining, sometimes an instructive, outlook into a teleological order of things, to which, without such a principle, mere physical observation would not lead us by itself. Thus some persons regard the tapeworm as given to the men or animals in whom it resides, as a kind of set-off for some defect in their vital organs; now I would ask if dreams (without which we never sleep, though we seldom remember them) may not be a purposive ordinance of nature? For during the relaxation of all the moving powers of the body, they serve to excite internally the vital organs by the medium of the Imagination and its great activity (which in this state generally rises to the height of affection). During sleep the Imagination commonly is more actively at play when the stomach is overloaded, in which case this excitement is the more necessary. Consequently, then, without this internal power of motion and this fatiguing unrest, on account of which we complain about our dreams (though in fact they are rather remedial), sleep even in a sound state of health would be a complete extinction of life.