ates in itself by distinguishing its
objects and its organs. Reference to external conditions, though seldom
explicit in these writers, who imagined they could appeal to an
introspection not revealing the external world, was pervasive in them;
as, for instance, where Hume made his fundamental distinction between
impressions and ideas, where the discrimination was based nominally on
relative vividness and priority in time, but really on causation
respectively by outer objects or by spontaneous processes in the brain.

[Sidenote: Hume's gratuitous scepticism.]

Hume it was who carried this psychological analysis to its goal, giving
it greater simplicity and universal scope; and he had also the further
advantage of not nursing any metaphysical changeling of his own to
substitute for the legitimate offspring of human understanding. His
curiosity was purer and his scepticism more impartial, so that he laid
bare the natural habits and necessary fictions of thought with singular
lucidity, and sufficient accuracy for general purposes. But the malice
of a psychology intended as a weapon against superstition here recoils
on science itself. Hume, like Berkeley, was extremely young, scarce
five-and-twenty, when he wrote his most incisive work; he was not ready
to propose in theory that test of ideas by their utility which in
practice he and the whole English school have instinctively adopted. An
ulterior test of validity would not have seemed to him satisfactory, for
though inclined to rebellion and positivism he was still the pupil of
that mythical philosophy which attributed the value of things to their
origin rather than to their uses, because it had first, in its parabolic
way, erected the highest good into a First Cause. Still breathing, in
spite of himself, this atmosphere of materialised Platonism, Hume could
not discover the true origin of anything without imagining that he had
destroyed its value. A natural child meant for him an illegitimate one;
his philosophy had not yet reached the wisdom of that French lady who
asked if all children were not natural. The outcome of his psychology
and criticism seemed accordingly to be an inhibition of reason; he was
left free to choose between the distractions of backgammon and "sitting
down in a forlorn scepticism."

In his first youth, while disintegrating reflection still overpowered
the active interests of his mind, Hume seems to have had some moments of
genuine suspense and dou