d to be possible according to merely mechanical laws, but to judge
them requires the causality of final causes--is insoluble so long as both
propositions are taken for constitutive principles; but it is soluble when
they are taken as regulative principles or standpoints for judgment. For it
is in no wise contradictory, on the one hand, to continue the search for
mechanical causes as far as this is in any way possible, and, on the other,
clearly to recognize that, at last, this will still leave a remainder which
we cannot make intelligible without calling to our aid the concept of ends.
Assuming that it were possible to carry the explanation of life from life,
from ancestral organisms (for the _generatio aequivoca_ is an absurd
theory) so far that the whole organic world should represent one great
family descended from one primitive form as the common mother, even
then the concept of final causes would only be pushed further back, not
eliminated: the origin of the first organization will always resist
mechanical explanation. Besides this mission of putting limits to causal
derivation and of filling the gap in knowledge by a necessary, although
subjective, way of looking at things, the Idea of ends has still another,
the direct promotion of knowledge from efficient causes through the
discovery of new causal problems. Thus, for example, physiology owes the
impulse to the discovery of previously unnoticed mechanical connections
(cf. also p. 382 note) to the question concerning the purpose of organs.
As doctrines mechanism and teleology are irreconcilable and impossible;
as rules or maxims of inquiry they are compatible, and the one as
indispensable as the other.

After the problem of life, which is insoluble by means of the mechanical
explanation, has necessitated the application of the concept of ends, the
teleological principle must, at least by way of experiment, be extended to
the whole of nature. This consideration culminates in the position that
man, as the subject of morality, must be held to be the final aim of the
world, for it is only in regard to a moral being that no further inquiry
can be raised as to the purpose of its existence. It also repeats the
moral argument for the existence of a supreme reason, thus supplementing
physico-theology, which is inadequate to the demonstration of one
absolutely perfect Deity; so that the third _Critique_, like the two
preceding, concludes with the Idea of God as an object of p