prehensible to us as colours
are to a man born blind, because we have not a sense adapted to them.
But, if we had a new sense, we should possibly no more doubt of their
existence than a blind man made to see does of the existence of light and
colours. I answer, first, if what you mean by the word Matter be only the
unknown support of unknown qualities, it is no matter whether there is
such a thing or no, since it no way concerns us; and I do not see the
advantage there is in disputing about what we know not what, and we know
not why.

78. But, secondly, if we had a new sense it could only furnish us with
new ideas or sensations; and then we should have the same reason against
their existing in an unperceiving substance that has been already offered
with relation to figure, motion, colour and the like. Qualities, as has
been shown, are nothing else but sensations or ideas, which exist only in
a mind perceiving them; and this is true not only of the ideas we are
acquainted with at present, but likewise of all possible ideas
whatsoever.

79. But, you will insist, what if I have no reason to believe the
existence of Matter? what if I cannot assign any use to it or explain
anything by it, or even conceive what is meant by that word? yet still it
is no contradiction to say that Matter exists, and that this Matter is in
general a substance, or occasion of ideas; though indeed to go about to
unfold the meaning or adhere to any particular explication of those words
may be attended with great difficulties. I answer, when words are used
without a meaning, you may put them together as you please without danger
of running into a contradiction. You may say, for example, that twice two
is equal to seven, so long as you declare you do not take the words of
that proposition in their usual acceptation but for marks of you know not
what. And, by the same reason, you may say there is an inert thoughtless
substance without accidents which is the occasion of our ideas. And we
shall understand just as much by one proposition as the other.

80. In the last place, you will say, what if we give up the cause of
material Substance, and stand to it that Matter is an unknown
somewhat--neither substance nor accident, spirit nor idea, inert,
thoughtless, indivisible, immovable, unextended, existing in no place.
For, say you, whatever may be urged against substance or occasion, or any
other positive or relative notion of Matter, has no place at all,