to the two kinds of universally accordant laws (the physical and those of final causes), although we cannot see into the way how this takes place. Hence we do not know how far the mechanical method of explanation which is possible for us may extend. So much only is certain that, so far as we can go in this direction, it must always be inadequate for things that we once recognise as natural purposes; and therefore we must, by the constitution of our Understanding, subordinate these grounds collectively to a teleological principle.

Hereon is based a privilege, and on account of the importance which the study of nature by the principle of mechanism has for the theoretical use of our Reason, also an appeal. We should explain all products and occurrences in nature, even the most purposive, by mechanism as far as is in