the reason to believe the existence of corporeal substances,
represented by his ideas, and exciting them in his mind, that you
can possibly have for believing the same thing? Of this there can be
no question- which one consideration were enough to make any
reasonable person suspect the strength of whatever arguments be may
think himself to have, for the existence of bodies without the mind.

  21. Were it necessary to add any farther proof against the existence
of Matter after what has been said, I could instance several of
those errors and difficulties (not to mention impieties) which have
sprung from that tenet. It has occasioned numberless controversies and
disputes in philosophy, and not a few of far greater moment in
religion. But I shall not enter into the detail of them in this place,
as well because I think arguments a posteriori are unnecessary for
confirming what has been, if I mistake not, sufficiently
demonstrated a priori, as because I shall hereafter find occasion to
speak somewhat of them.

  22. I am afraid I have given cause to think I am needlessly prolix
in handling this subject. For, to what purpose is it to dilate on that
which may be demonstrated with the utmost evidence in a line or two,
to any one that is capable of the least reflexion? It is but looking
into your own thoughts, and so trying whether you can conceive it
possible for a sound, or figure, or motion, or colour to exist without
the mind or unperceived. This easy trial may perhaps make you see that
what you contend for is a downright contradiction. Insomuch that I
am content to put the whole upon this issue:- If you can but
conceive it possible for one extended movable substance, or, in
general, for any one idea, or anything like an idea, to exist
otherwise than in a mind perceiving it, I shall readily give up the
cause. And, as for all that compages of external bodies you contend
for, I shall grant you its existence, though you cannot either give me
any reason why you believe it exists, or assign any use to it when
it is supposed to exist. I say, the bare possibility of your
opinions being true shall pass for an argument that it is so.

  23. But, say you, surely there is nothing easier than for me to
imagine trees, for instance, in a park, or books existing in a closet,
and nobody by to perceive them. I answer, you may so, there is no
difficulty in it; but what is all this, I beseech you, more than
framing in your mind certain ideas which you call books and trees, and
the same time omitting to frame the idea of any one that may
perceive them? But do not you yourself perceive or think of them all
the while? This therefore is nothing to the purpose; it only shews you
have the power of imagining or forming ideas in your mind: but it does
not shew that you can conceive it possible the objects of your thought
may exist without the mind. To make out this, it is necessary that you
conceive them existing unconceived or unthought of, which is a
manifest repugnancy. When we do our utmost to conceive the existence
of external bodies, we are all the while only contemplating our own
ideas. But the mind taking no notice of itself, is deluded to think it
can and does conceive bodies existing unthought of or without the
mind, though at the same time they are apprehended by or exist in
itself. A little attention will discover to any one the truth and
evidence of what is here said, and make it unnecessary to insist on
any other proofs against the existence of material substance.

  24. It is very obvious, upon the least inquiry into our thoughts, to
know whether it is possible for us to understand what is meant by
the absolute existence of sensible objects in themselves, or without
the mind. To me it is evident those words mark out either a direct
contradiction, or else nothing at all. And to convince others of this,
I know no readier or fairer way than to entreat they would calmly
attend to their own thoughts; and if by this attention the emptiness
or repugnancy of those expressions does appear, surely nothing more is
requisite for the conviction. It is on this therefore that I insist,
to wit, that the absolute existence of unthinking things are words
without a meaning, or which include a contradiction. This is what I
repeat and inculcate, and earnestly recommend to the attentive
thoughts of the reader.

  25. All our ideas, sensations, notions, or the things which we
perceive, by whatsoever names they may be distinguished, are visibly
inactive- there is nothing of power or agency included in them. So
that one idea or object of thought cannot produce or make any
alteration in another. To be satisfied of the truth of this, there
is nothing else requisite but a bare observation of our ideas. For,
since they and every part of them exist only in the mind, it follows
that there is nothing in them but what is perceived: but whoever shall
attend to his ideas, whether of sense or reflexion, will not
perceive in them any power or activity; there is, therefore, no such
thing contained in them. A little attention will discover to us that
the very being of an idea implies passiveness and inertness in it,
insomuch that it is impossible for an idea to do anything, or,
strictly speaking, to be the cause of anything: neither can it be
the resemblance or pattern of any active being, as is evident from
sect. 8. Whence it plainly follows that extension, figure, and
motion cannot be the cause of our sensations. To say, therefore,
that these are the effects of powers resulting from the configuration,
number, motion, and size of corpuscles, must certainly be false.

  26. We perceive a continual succession of ideas, some are anew
excited, others are changed or totally disappear. There is therefore
some cause of these ideas, whereon they depend, and which produces and
changes them. That this cause cannot be any quality or idea or
combination of ideas, is clear from the preceding section. I must
therefore be a substance; but it has been shewn that there is no
corporeal or material substance: it remains therefore that the cause
of ideas is an incorporeal active substance or Spirit.