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 favour[110] which nature has felt 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.
§ 68. Of the principle of Teleology as internal principle of natural science
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 not 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.
If then we introduce into the context of natural science the concept of God in order to explain the purposiveness in nature, and subsequently use this purposiveness to prove that there is a God, there is no internal consistency in either science [i.e. either in natural science or theology]; and a delusive circle brings them both into uncertainty, because they have allowed their boundaries to overlap.
The expression, a purpose of nature, already sufficiently prevents the confusion of mixing up natural science and the occasion that it gives for judging teleologically of its objects, with the consideration of God, and so of a theological derivation of them. We must not regard it as insignificant, if one interchanges this expression with that of a divine purpose in the ordering of nature, or gives out the latter as more suitable and proper for a pious soul, because it must come in the end to deriving these purposive forms in nature from a wise author of the world. On the contrary, we must carefully and modestly limit ourselves to the expression, a purpose of nature, which asserts exactly as much as we know. Before we ask after the cause of nature itself, we find in nature, and in the course of its development, products of the same kind which are developed in it according to known empirical laws, in accordance with which natural science must judge of its objects, and, consequently, must seek in nature their causality according to the rule of purposes. So then it must not transgress its bounds in order to introduce into itself as a domestic principle that, to whose concept no experience can be commensurate, upon which we are only entitled to venture after the completion of natural science.
Natural characteristics which demonstrate themselves a priori, and consequently admit of insight into their possibility from universal principles without any admixture of experience, although they carry with them a technical purposiveness, yet cannot, because they are absolutely necessary, be referred to the Teleology of nature, as to a method belonging to Physic for solving its problems. Arithmetical or geometrical analogies, as well as universal mechanical laws,—however strange and admirable may seem to us the union of different rules, quite independent of one another according to all appearance, in a single principle,—possess on that account no claim to be teleological grounds of explanation in Physic. Even if they deserve to be brought into consideration in the universal theory of the purposiveness of things of nature, yet they belong to another [science], i.e. Metaphysic, and constitute no internal principle of natural science; as with the empirical laws of natural purposes in organised beings, it is not only permissible but unavoidable to use the teleological mode of judging as a principle of the doctrine of nature in regard to a particular class of its objects.
So to the end that Physic may keep within its own bounds, it abstracts itself entirely from the question, whether natural purposes are designed or undesigned; for that would be to meddle in an extraneous business, in Metaphysic. It is enough that there are objects, alone explicable according to natural laws which we can only think by means of the Idea of purposes as principle, and also alone internally cognisable as concerns their internal form, in this way. In order, therefore, to remove the suspicion of the slightest assumption,—as if we wished to mix with our grounds of cognition something not belonging to Physic at all, viz. a supernatural cause,—we speak in Teleology, indeed, of nature as if the purposiveness therein were designed, but in such a way that this design is ascribed to nature, i.e. to matter. Now in this way there can be no misunderstanding, because no design in the proper meaning of the word can possibly be ascribed to inanimate matter; we thus give notice that this word here only expresses a principle of the reflective not of the determinant Judgement, and so is to introduce no particular ground of causality; but only adds for the use of the Reason a different kind of investigation from that according to mechanical laws, in order to supplement the inadequacy of the latter even for empirical research into all particular laws of nature. Hence we speak quite correctly in Teleology, so far as it is referred to Physic, of the wisdom, the economy, the forethought, the beneficence of Nature, without either making an intelligent being of it, for that would be preposterous; or even without presuming to place another intelligent Being above it as its Architect, for that would be presumptuous.[111] But there should be only signified thereby a kind of causality of nature after the analogy of our own in the technical use of Reason, in order to have before us the rule according to which certain products of nature must be investigated.
But now why is it that Teleology usually forms no proper part of theoretical natural science, but is regarded as a propaedeutic or transition to Theology? This is done in order to restrict the study of nature, mechanically considered, to that which we can so subject to observation or experiment that we are able to produce it ourselves as nature does, or at least by similar laws. For we see into a thing completely only so far as we can make it in accordance with our concepts and bring it to completion. But organisation, as an inner purpose of nature, infinitely surpasses all our faculty of presenting the like by means of art. And as concerns the external contrivances of nature regarded as purposive (wind, rain, etc.), Physic, indeed, considers their mechanism, but it cannot at all present their reference to purposes, so far as this is a condition necessarily belonging to cause; for this necessity of connexion has to do altogether with the combination of our concepts and not with the constitution of things.