to contain a perfectly true statement, but it is only half
the truth. It is no doubt true that our visual ideas are a kind of
language by which we are informed of the tactile ideas which may or
will arise in us; but this is true, more or less, of every sense in
regard to every other. If I put my hand in my pocket, the tactile
ideas which I receive prophesy quite accurately what I shall
see--whether a bunch of keys or half-a-crown--when I pull it out
again; and the tactile ideas are, in this case, the language which
informs me of the visual ideas which will arise. So with the other
senses: olfactory ideas tell me I shall find the tactile and visual
phenomena called violets, if I look for them; taste tells me that
what I am tasting will, if I look at it, have the form of a clove; and
hearing warns me of what I shall, or may, see and touch every minute
of my life.

But while the "New Theory of Vision" cannot be considered to possess
much value in relation to the immediate object its author had in view,
it had a vastly important influence in directing attention to the real
complexity of many of those phenomena of sensation, which appear at
first to be simple. And even if Berkeley was, as I imagine he was,
quite wrong in supposing that we do not see space, the contrary
doctrine makes quite as strongly for his general view, that space can
be conceived only as something thought by a mind.

The last of Locke's "primary qualities" which remain to be considered
is mechanical solidity, or impenetrability. But our conception of this
is derived from the sense of resistance to our own effort, or active
force, which we meet with in association with sundry tactile or visual
phenomena; and, undoubtedly, active force is inconceivable except as a
state of consciousness. This may sound paradoxical; but let anyone try
to realize what he means by the mutual attraction of two particles,
and I think he will find, either, that he conceives them simply as
moving towards one another at a certain rate, in which case he only
pictures motion to himself, and leaves force aside; or, that he
conceives each particle to be animated by something like his own
volition, and to be pulling as he would pull. And I suppose that this
difficulty of thinking of force except as something comparable to
volition, lies at the bottom of Leibnitz's doctrine of monads, to say
nothing of Schopenhauer's "Welt als Wille und Vorstellung;" while the
opposite difficulty of