Page 64 of 93
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 is284 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.
285 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 persons286 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.
Also the beauty of nature, i.e. its connexion with the free play of our cognitive faculties in apprehending and judging of its appearance, can be regarded as a kind of objective purposiveness of nature in its whole [content] as a system of which man is a member; if once the teleological judging of the same by means of the natural purposes which organised beings suggest to us, has justified for us the Idea of a great system of purposes of nature. We can regard it as a favour110 which nature has felt287 for us, that in addition to what is useful it has so profusely dispensed beauty and charm; and we can therefore love it, as well as regard it with respect on account of its immensity, and feel ourselves ennobled by such regard; just as if nature had established and adorned its splendid theatre precisely with this view.
We shall say only one thing more in this paragraph. If we have once discovered in nature a faculty of bringing forth products that can only be thought by us in accordance with the concept of final causes, we go further still. We venture to judge that things belong to a system of purposes, which yet do not (either in themselves or in their purposive relations) necessitate our seeking for any principle of their possibility beyond the mechanism of causes working blindly. For the first Idea, as concerns its ground, already brings us beyond the world of sense; since the unity of the supersensible principle must be regarded as valid in this way not merely for certain species of natural beings, but for the whole of nature as a system.
The principles of a science are either internal to it and are then called domestic (principia domestica), or are based on concepts that can only find their place outside it and so are foreign principles (peregrina). Sciences that contain the latter, place at the basis of their doctrines auxiliary propositions (lemmata), i.e. they borrow some concept, and with it a ground of arrangement, from another science.
Every science is in itself a system, and it is not288 enough in it to build in accordance with principles and thus to employ a technical procedure, but we must go to work with it architectonically, as a building subsisting for itself; we must not treat it as an additional wing or part of another building, but as a whole in itself, although we may subsequently make a passage from it into that other or conversely.
