m to consider, that, if all be a dream, then he doth but
dream that he makes the question, and so it is not much matter that a
waking man should answer him. But yet, if he pleases, he may dream that
I make him this answer, That the certainty of things existing in RERUM
NATURA when we have the testimony of our senses for it is not only as
great as our frame can attain to, but as our condition needs. For,
our faculties being suited not to the full extent of being, nor to a
perfect, clear, comprehensive knowledge of things free from all doubt
and scruple; but to the preservation of us, in whom they are; and
accommodated to the use of life: they serve to our purpose well enough,
if they will but give us certain notice of those things, which are
convenient or inconvenient to us. For he that sees a candle burning, and
hath experimented the force of its flame by putting his finger in it,
will little doubt that this is something existing without him, which
does him harm, and puts him to great pain: which is assurance enough,
when no man requires greater certainty to govern his actions by than
what is as certain as his actions themselves. And if our dreamer pleases
to try whether the glowing heat of a glass furnace be barely a wandering
imagination in a drowsy man's fancy, by putting his hand into it, he may
perhaps be wakened into a certainty greater than he could wish, that it
is something more than bare imagination. So that this evidence is as
great as we can desire, being as certain to us as our pleasure or pain,
i.e. happiness or misery; beyond which we have no concernment, either of
knowing or being. Such an assurance of the existence of things without
us is sufficient to direct us in the attaining the good and avoiding the
evil which is caused by them, which is the important concernment we have
of being made acquainted with them.

9. But reaches no further than actual Sensation.

In fine, then, when our senses do actually convey into our
understandings any idea, we cannot but be satisfied that there doth
something AT THAT TIME really exist without us, which doth affect our
senses, and by them give notice of itself to our apprehensive faculties,
and actually produce that idea which we then perceive: and we cannot
so far distrust their testimony, as to doubt that such COLLECTIONS of
simple ideas as we have observed by our senses to be united together, do
really exist together. But this knowledge extends as far as the pres