deny that any man believes in
the independent existence of matter. And in this denial they are most
indubitably right. For observe what such a belief requires as its
condition. A man must disengage in thought, a tree, for instance, from
the thought of all perception of it, and then he must believe in its
existence thus disengaged. If he has not disengaged, in his mind, the
tree from its perception, (from its present perception, if the tree be
before him--from its remembered perception, if it be not before him,) he
cannot believe in the existence of the tree disengaged from its
perception; for the tree is not disengaged from its perception. But
unless he believes in the existence of the tree disengaged from its
perception, he does not believe in the independent existence of the
tree,--in the existence of the tree _per se_. Now, can the mind by any
effort effect this disengagement? The thing is an absolute
impossibility. The condition on which the belief hinges cannot be
purified, and consequently the belief itself cannot be entertained.

People have, then, _no belief_ in the independent existence of
matter--that is, in the existence of matter entirely denuded of
perception. This point being proved, what becomes of Dr Reid's appeal to
_this belief_ in support of matter's independent existence? It has not
only no force; it has no meaning. This second tactic is invincible.
Scepticism and idealism are perfectly in the right when they refuse to
accept as the guarantee of independent matter a belief which itself has
no manner of existence. How can they be vanquished by an appeal to a
nonentity?

A question may here be raised. If the belief in question be not the
fact, what has hitherto prevented scepticism from putting a final
extinguisher on Reid's appeal by _proving_ that no such belief exists? A
very sufficient reason has prevented scepticism, from doing this--from
explicitly extinguishing the appeal. There is a division of labour in
speculation as well as in other pursuits. It is the sceptic's business
simply to deny the existence of the belief: it is no part of his
business to exhibit the grounds of his denial. _We_ have explained these
grounds; but were the sceptic to do this, he would be travelling out of
his vocation. Observe how the case stands. The reason why matter _per
se_ is not and cannot be believed in, is because it is impossible for
thought to disengage matter from perception, and consequently it is
impossib