ph operator is of his instrument.

It is hardly necessary to point out that the doctrine just laid down is
what is commonly called materialism. In fact, I am not sure that the
adjective "crass," which appears to have a special charm for rhetorical
sciolists, would not be applied to it. But it is, nevertheless, true
that the doctrine contains nothing inconsistent with the purest
idealism. For, as Hume remarks (as indeed Descartes had observed long
before):--

"'Tis not our body we perceive when we regard our limbs and
members, but certain impressions which enter by the senses; so that
the ascribing a real and corporeal existence to these impressions,
or to their objects, is an act of the mind as difficult to explain
as that [the external existence of objects] which we examine at
present."--(I. p. 249.)

Therefore, if we analyse the proposition that all mental phenomena are
the effects or products of material phenomena, all that it means amounts
to this; that whenever those states of consciousness which we call
sensation, or emotion, or thought, come into existence, complete
investigation will show good reason for the belief that they are
preceded by those other phenomena of consciousness to which we give the
names of matter and motion. All material changes appear, in the long
run, to be modes of motion; but our knowledge of motion is nothing but
that of a change in the place and order of our sensations; just as our
knowledge of matter is restricted to those feelings of which we assume
it to be the cause.

It has already been pointed out, that Hume must have admitted, and in
fact does admit, the possibility that the mind is a Leibnitzian monad,
or a Fichtean world-generating Ego, the universe of things being merely
the picture produced by the evolution of the phenomena of consciousness.
For any demonstration that can be given to the contrary effect, the
"collection of perceptions" which makes up our consciousness may be an
orderly phantasmagoria generated by the Ego, unfolding its successive
scenes on the background of the abyss of nothingness; as a firework,
which is but cunningly arranged combustibles, grows from a spark into a
coruscation, and from a coruscation into figures, and words, and
cascades of devouring fire, and then vanishes into the darkness of the
night.

On the other hand, it must no less readily be allowed that, for anything
that can be proved to the contrary, there ma