without a material mechanism--at least a represented
one--lying beneath and between. Spinoza made a great improvement in the
system by attaching the mind more systematically to the body, and
studying the parts which organ and object played in qualifying
knowledge; but his conception of mental unities and mental processes
remained literary, or at best, as we have seen, dialectical. No shadow
of a principle at once psychic and genetic appeared in his philosophy.
All mind was still a transcript of material facts or a deepening of
moral relations.

[Sidenote: Association not efficient]

The idea of explaining the flow of ideas without reference to bodies
appeared, however, in the principle of association. This is the nearest
approach that has yet been made to a physics of disembodied
mind--something which idealism sadly needs to develop. A terrible
incapacity, however, appears at once in the principle of association;
for even if we suppose that it could account for the flow of ideas, it
does not pretend to supply any basis for sensations. And as the more
efficient part of association--association by contiguity--is only a
repetition in ideas of the order once present in impressions, the whole
question about the march of mental experience goes back to what
association does not touch, namely, the origin of sensations. What
everybody assumed, of course, was that the order and quality of
sensations were due to the body; but their derivation was not studied.
Hume ignored it as much as possible, and Berkeley did not sacrifice a
great deal when he frankly suggested that the production of sensation
must be the direct work of God.

This tendency not to recognise the material conditions of mind showed
itself more boldly in the treatment of ideation. We are not plainly
aware (in spite of headaches, fatigue, sleep, love, intoxication, and
madness) that the course of our thoughts is as directly dependent on the
body as is their inception. It was therefore possible, without glaring
paradox, to speak as if ideas caused one another. They followed, in
recurring, the order they had first had in experience, as when we learn
something by heart. Why, a previous verse being given, we should
sometimes be unable to repeat the one that had often followed it before,
there was no attempt to explain: it sufficed that reverie often seemed
to retrace events in their temporal order. Even less dependent on
material causes seemed to be the other sort of