(a priori).

And if, starting from the forms of the objects of experience, from below upwards (a posteriori), we wish to explain the purposiveness, which we believe is met with in experience, by appealing to a cause working in accordance with purposes, then is our explanation quite tautological and we are only mocking Reason with words. Indeed when we lose ourselves with this way of explanation in the transcendent, whither natural knowledge cannot follow, Reason is seduced into poetical extravagance, which it is its peculiar destination to avoid.

On the other hand, it is just as necessary a maxim of Reason not to pass by the principle of purposes in the products of nature. For, although it does not make their mode of origination any more comprehensible, yet