Critique of Judgement by Immanuel Kant Chapter 83 Page 5

As the only being on earth which has an Understanding and, consequently, a faculty of setting arbitrary purposes before itself, he is certainly entitled to be the lord of nature; and if it be regarded as a teleological system he is, by his destination, the ultimate purpose of nature. But this is subject to the condition of his having an Understanding and the Will to give to it and to himself such a reference to purposes, as can be self-sufficient independently of nature, and, consequently, can be a final purpose; which, however, must not be sought in nature itself.

But in order to find out where in man we have to place that ultimate purpose of nature, we must seek out what nature can supply to prepare him for what he must do himself in order to be a final purpose, and we must separate it from all those purposes