KANT'S CRITIQUE OF TELEOLOGY IN BIOLOGICAL EXPLANATION

158 Heuristic but Necessary Principles
defined as something that we cannot explain merely mechanistically;
since we can conceive real causes only as mechanistic, we
must take refuge in ideal causes whenever the mechanistically conceived
causes are insufficient. The necessity of the second maxim
(R2) is thus a conceptual or analytical necessity in the hypothetical
case that there should in fact be things that we have to consider as
natural purposes. If organisms should turn out to be explainable in
mechanistic terms, i.e. if they should turn out not to be natural purposes
(and assuming there are no other suitable candidates for the
position), then the second maxim would not be necessary, it would
not be "prompted by special experiences" (§70, B314; CJ, 267), and
there would be no antinomy. There would be, so to speak, only the
speculative possibility of an antinomy, if somewhere, sometime a
genuine natural purpose should turn up. But it should not be forgotten
that while it is theoretically possible that what we take to be a
natural purpose might in fact be explained in a purely mechanistic
manner, it is practically speaking as good as impossible. To accomplish
this, we would have to know all the properties of all the parts
(and their parts) as well as all the empirical regularities and laws
that apply to them. The task is not logically impossible but practically
hopeless:
For it is quite certain that in terms of merely mechanical principles of nature
we cannot even adequately become familiar with, much less explain,
organized beings and how they are internally possible. So certain is this that
we may boldly state that it is absurd for human beings even to attempt it, or
to hope that perhaps some day another Newton might arise who would
explain to us, in terms of natural laws unordered by any intention, how even
a mere blade of grass is produced. Rather, we must absolutely deny that
human beings have such insight. (§75, B337-8; CJ, 282)
Regulative and Constitutive Principles
After the formal presentation of the antinomy of judgment
Kant warns against "transforming" the regulative maxims into
constitutive principles, since the latter would produce a quite different
opposition than the conflict that is important for the Dialectic.
Nonetheless, he then proceeds formally to present this second, spurious
opposition in exact parallel to the opposition of the maxims. In
the course of the reception of the work this parallelism has given