methods of Biology--methods which are obviously identical
with those of all other sciences, and therefore wholly incompetent to
form the ground of any distinction between it and them.[8]

But I shall be asked at once, Do you mean to say that there is no
difference between the habit of mind of a mathematician and that of a
naturalist? Do you imagine that Laplace might have been put into the
Jardin des Plantes, and Cuvier into the Observatory, with equal
advantage to the progress of the sciences they professed?

To which I would reply, that nothing could be further from my thoughts.
But different habits and various special tendencies of two sciences do
not imply different methods. The mountaineer and the man of the plains
have very different habits of progression, and each would be at a loss
in the other's place; but the method of progression, by putting one leg
before the other, is the same in each case. Every step of each is a
combination of a lift and a push; but the mountaineer lifts more and the
lowlander pushes more. And I think the case of two sciences resembles
this.

I do not question for a moment, that while the Mathematician is busied
with deductions _from_ general propositions, the Biologist is more
especially occupied with observation, comparison, and those processes
which lead _to_ general propositions. All I wish to insist upon is, that
this difference depends not on any fundamental distinction in the
sciences themselves, but on the accidents of their subject-matter, of
their relative complexity, and consequent relative perfection.

The Mathematician deals with two properties of objects only, number and
extension, and all the inductions he wants have been formed and finished
ages ago. He is occupied now with nothing but deduction and
verification.

The Biologist deals with a vast number of properties of objects, and
his inductions will not be completed, I fear, for ages to come; but when
they are, his science will be as deductive and as exact as the
Mathematics themselves.

Such is the relation of Biology to those sciences which deal with
objects having fewer properties than itself. But as the student, in
reaching Biology, looks back upon sciences of a less complex and
therefore more perfect nature; so, on the other hand, does he look
forward to other more complex and less perfect branches of knowledge.
Biology deals only with living beings as isolated things--treats only of
the life of the individua