thing more than barely that idea
in our minds; whether we can thence certainly infer the existence of
anything without us, which corresponds to that idea, is that whereof
some men think there may be a question made; because men may have such
ideas in their minds, when no such thing exists, no such object affects
their senses. But yet here I think we are provided with an evidence that
puts us past doubting. For I ask any one, Whether he be not invincibly
conscious to himself of a different perception, when he looks on the sun
by day, and thinks on it by night; when he actually tastes wormwood, or
smells a rose, or only thinks on that savour or odour? We as plainly
find the difference there is between any idea revived in our minds by
our own memory, and actually coming into our minds by our senses, as we
do between any two distinct ideas. If any one say, a dream may do the
same thing, and all these ideas may be produced, in us without
any external objects; he may please to dream that I make him this
answer:--I. That it is no great matter, whether I remove his scruple or
no: where all is but dream, reasoning and arguments are of no use, truth
and knowledge nothing. 2. That I believe he will allow a very manifest
difference between dreaming of being in the fire, and being actually in
it. But yet if he be resolved to appear so sceptical as to maintain,
that what I call being actually in the fire is nothing but a dream;
and that we cannot thereby certainly know, that any such thing as fire
actually exists without us: I answer, That we certainly finding that
pleasure or pain follows upon the application of certain objects to us,
whose existence we perceive, or dream that we perceive, by our senses;
this certainty is as great as our happiness or misery, beyond which we
have no concernment to know or to be. So that, I think, we may add
to the two former sorts of knowledge this also, of the existence of
particular external objects, by that perception and consciousness we
have of the actual entrance of ideas from them, and allow these three
degrees of knowledge, viz. INTUITIVE, DEMONSTRATIVE, and SENSITIVE;
in each of which there are different degrees and ways of evidence and
certainty.

15. Knowledge not always clear, where the Ideas that enter into it are
clear.

But since our knowledge is founded on and employed about our ideas only,
will it not follow from thence that it is conformable to our ideas; and
that where our idea