— 650 —
The application voluntary; but we know as things are, not as we please.
      §2. There is also another thing in a Man’s Power, and that is,
though he turns his Eyes sometimes towards an Object, yet he may
chuse whether he will curiously survey it, and with an intent
application, endeavour to observe accurately all that is visible in it.
But yet what he does see, he cannot see otherwise than he does. It
depends not on his Will to see that Black, which appears Yellow; nor
to persuade himself, that what actually scalds him, feels cold: The
Earth will not appear painted with Flowers, nor the Fields covered
with Verdure, whenever he has a Mind to it: in the cold Winter, he
cannot help seeing it white and hoary, if he will look abroad. Just
thus is it with our Understanding, all that is voluntary in our Know-
ledge, is the employing, or with-holding any of our Faculties from
this or that sort of Objects, and a more, or less accurate survey of
them: But they being employed, our Will hath no Power to determine
— 651 —
the Knowledge of the Mind one way or other; that is done only by the
Objects themselves, as far as they are clearly discovered. And
therefore, as far as Men’s Senses are conversant about external
Objects, the Mind cannot but receive those Ideas, which are presented
by them, and be informed of the Existence of Things without: and
so far as Men’s Thoughts converse with their own determined
Ideas, they cannot but, in some measure, observe the Agreement,
and Disagreement that is to be found amongst some of them, which
is so far Knowledge: and if they have Names for those Ideas which
they have thus considered, they must needs be assured of the Truth
of those Propositions, which express that Agreement, or Disagree-
ment, they perceive in them, and be undoubtedly convinced of
those Truths. For what a Man sees, he cannot but see; and what
he perceives, he cannot but know that he perceives.
Locke Hum IV, 13, §2, pp. 650-651