_specific_ experience, and argue wholly _upwards_
from particular facts to a general conclusion; while those who are
called theorists aim at embracing a wider field of experience, and,
having argued upwards from particular facts to a general principle
including a much wider range than that of the question under discussion,
then argue _downwards_ from that general principle to a variety of
specific conclusions.

Suppose, for example, that the question were, whether absolute kings
were likely to employ the powers of government for the welfare or for
the oppression of their subjects. The practicals would endeavour to
determine this question by a direct induction from the conduct of
particular despotic monarchs, as testified by history. The theorists
would refer the question to be decided by the test not solely of our
experience of kings, but of our experience of men. They would contend
that an observation of the tendencies which human nature has manifested
in the variety of situations in which human beings have been placed, and
especially observation of what passes in our own minds, warrants us in
inferring that a human being in the situation of a despotic king will
make a bad use of power; and that this conclusion would lose nothing of
its certainty even if absolute kings had never existed, or if history
furnished us with no information of the manner in which they had
conducted themselves.

The first of these methods is a method of induction, merely; the last a
mixed method of induction and ratiocination. The first may be called the
method _a posteriori;_ the latter, the method _a priori_. We are aware
that this last expression is sometimes used to characterize a supposed
mode of philosophizing, which does not profess to be founded upon
experience at all. But we are not acquainted with any mode of
philosophizing, on political subjects at least, to which such a
description is fairly applicable. By the method _a posteriori_ we mean
that which requires, as the basis of its conclusions, not experience
merely, but specific experience. By the method _a priori_ we mean (what
has commonly been meant) reasoning from an assumed hypothesis; which is
not a practice confined to mathematics, but is of the essence of all
science which admits of general reasoning at all. To verify the
hypothesis itself _a posteriori_, that is, to examine whether the facts
of any actual case are in accordance with it, is no part of the business
of scie