Hence the concept of a Deity, which would be adequate for our teleological judging of nature, can never be derived from mere theoretical principles of the use of Reason (on which Physico-theology alone is based). For as one alternative we may explain all Teleology as a mere deception of the Judgement in its judging of the causal combination of things, and fly to the sole principle of a mere mechanism of nature, which merely seems to us, on account of the unity of the Substance of whose determinations nature is but the manifold, to contain a universal reference to purposes. Or if, instead of this Idealism of final causes, we wish to remain attached to the principle of the Realism of this particular kind of causality, we may set beneath natural purposes many intelligent original beings or only a single one. But so far as we have for the basis of this concept [of Realism] only empirical principles derived from the actual purposive combination in the world, we cannot on the one hand find any remedy for the discordance that nature presents in many examples in respect of unity of purpose; and on the other hand, as to the concept of a single intelligent Cause, so far as we are authorised by mere experience, we can never draw it therefrom in a manner sufficiently determined for any serviceable Theology whatever (whether theoretical or practical). Physical Teleology impels us, it is true, to seek a Theology; but it cannot produce one, however far we may investigate nature by means of experience and, in reference to the purposive combination apparent in it, call in Ideas of Reason (which must be theoretical for physical problems). What is the use, one might well complain, of placing at the basis of all these arrangements a great Understanding incommensurable by us, and supposing it to govern the world according to design, if nature does not and cannot tell us anything of the final design? For without this we cannot refer all these natural purposes to any common point, nor can we form any teleological principle, sufficient either for cognising the purposes collected in a system, or for forming a concept of the Supreme Understanding, as Cause of such a nature, that could serve as a standard for our Judgement reflecting teleologically thereon. I should thus have an _artistic Understanding_ for scattered purposes, but no _Wisdom_ for a final purpose, in which final purpose nevertheless must be contained the determining ground of the said Understanding. But in the absence of a final purpose which pure Reason alone can supply (because all purposes in the world are empirically conditioned, and can contain nothing absolutely good but only what is good for this or that regarded as a contingent design), and which alone would teach me what properties, what degree, and what relation of the Supreme Cause to nature I have to think in order to judge of nature as a teleological system; how and with what right do I dare to extend at