2. Instance: whiteness of this paper.
It is therefore the actual receiving of ideas from without that gives us notice
of the existence of other things, and makes us know, that something doth exist at that time without us, which
causes that idea in us; though perhaps we neither know nor consider how it does it. For it takes not from the
certainty of our senses, and the ideas we receive by them, that we know not the manner wherein they are
produced: v.g. whilst I write this, I have, by the paper affecting my eyes, that idea produced in my mind, which,
whatever object causes, I call white; by which I know that that quality or accident (i.e., whose appearance before
my eyes always causes that idea) doth really exist, and hath a being without me. And of this, the greatest
assurance I can possibly have, and to which my faculties can attain, is the testimony of my eyes, which are the
proper and sole judges of this thing; whose testimony I have reason to rely on as so certain, that I can no more
doubt, whilst I write this, that I see white and black, and that something really exists that causes that sensation in
me, than that I write or move my hand; which is a certainty as great as human nature is capable of, concerning the
existence of anything, but a man's self alone, and of God.