tail for steering, etc., we say that all this is contingent in the highest degree according to the mere nexus effectivus of nature, without calling in the aid of a particular kind of causality, namely that of purpose (nexus finalis). In other words, nature, considered as mere mechanism, could have produced its forms in a thousand other ways without stumbling upon the unity which is in accordance with such a principle.

It is not in the concept of nature but quite apart from it that we can hope to find the least ground a priori for this.

Nevertheless the teleological act of judgement is rightly brought to bear, at least problematically, upon the investigation of nature; but only in order to bring it under principles of observation and inquiry according to the