o his interpretation of the
facts, because it maintains that these facts might _equally well_ be
ascribed to intelligent design. And so undoubtedly they might, if we
were all childish enough to rush into a supernatural explanation
whenever a natural explanation is found sufficient to account for the
facts. Once admit the glaringly illogical principle that we may assume
the operation of higher causes where the operation of lower ones is
sufficient to explain the observed phenomena, and all our science and
all our philosophy are scattered to the winds. For the law of logic
which Sir William Hamilton called the law of parsimony--or the law which
forbids us to assume the operation of higher causes when lower ones are
found sufficient to explain the observed effects--this law constitutes
the only logical barrier between science and superstition. For it is
manifest that it is always possible to give a hypothetical explanation
of any phenomenon whatever, by referring it immediately to the
intelligence of some supernatural agent; so that the only difference
between the logic of science and the logic of superstition consists in
science recognising a validity in the law of parsimony which
superstition disregards. Therefore I have no hesitation in saying that
this way of looking at the evidence in favour of natural selection is
not a scientific or a reasonable way of looking at it, but a purely
superstitious way. Let us take, for instance, as an illustration, a
perfectly parallel case. When Kepler was unable to explain by any known
causes the paths described by the planets, he resorted to a supernatural
explanation, and supposed that every planet was guided in its movements
by some presiding angel. But when Newton supplied a beautifully simple
physical explanation, all persons with a scientific habit of mind at
once abandoned the metaphysical explanation. Now, to be consistent, the
above-mentioned professors, and all who think with them, ought still to
adhere to Kepler's hypothesis in preference to Newton's explanation;
for, excepting the law of parsimony, there is certainly no other logical
objection to the statement that the movements of the planets afford as
good evidence of the influence of guiding angels as they do of the
influence of gravitation.

So much, then, for the absurdly illogical position that, granting the
evidence in favour of natural selection and supernatural design to be
equal and parallel, we should hesitate f