end when it was shown that the motions of the
planets were regulated by Newton's law, _and that there was
no room left for the activities of a guiding power_.
Likewise, in the realm of instincts, when it can be shown
that these instincts may be reduced to elementary
physico-chemical laws, the assumption of design becomes
superfluous." (_Italics mine._)

In the first place the "purposefulness" of the movements of the planets
is not affected in the very least by the question of heliocentricism.
What the author is probably thinking of is an exaggerated and obsolete
teleology, but that is not what seems to be the purport of the passage.
Let that pass. The main confusion lies in the application of the term
"Law." The Ten Commandments, and our familiar friend D.O.R.A., are laws
we must obey or take the consequences of our disobedience. The "laws"
which the writer is dealing with are not anything of this kind. Newton's
Law is not a thing made by Newton, but an orderly system of events which
was in existence long before Newton's time, but was first demonstrated
by him. It tells us how a certain part of the system works--when we are
"_inside it_." It does not in the least explain the system any more than
the discovery of the resiliency of the spring of the watch explains the
watch itself. So far from dispensing with "the activities of a guiding
power," Newton's law is positively clamant for a final explanation,
since it does not tell us, nor does it pretend to tell us, how the "law"
came into existence, still less how the planets came to be there, or how
they happen to be in a state of motion at all. Writers of this kind
never seem to have grasped the significance of such simple matters as
the different kinds of causes, or to be aware that a formal cause is not
an efficient cause, and that neither of them is a final cause. Coming to
the latter part of the paragraph, it is in no way proved that instincts
can be reduced to physico-chemical laws, and, suppose it were proved,
the assumption of design would be exactly where it is at this moment. It
is the old story of St. Thomas Aquinas and Avicenna and their discussion
on abiogenesis, and surely biologists might be expected to have heard of
that. The same confusion of thought is to be met with elsewhere in this
book, and in other similar books, and a few instances may now be
examined.

Samuel Butler, in _Life and Habit_, warns his readers against the d