— 619 —
Man knows that he himself is.
      §2. I think it is beyond Question, that Man has a clear Perception of
his own Being; he knows certainly, that he exists, and that he is
something. He that can doubt, whether he be any thing, or no, I
speak not to, no more than I would argue with pure nothing, or
endeavour to convince Non-entity, that it were something. If any
one pretends to be so sceptical, as to deny his own Existence, (for
— 620 —
really to doubt of it, is manifestly impossible,) let him for me enjoy
his beloved Happiness of being nothing, until Hunger, or some
other Pain convince him of the contrary. This then, I think, I may
take for a Truth, which every ones certain Knowledge assures him
of, beyond the liberty of doubting, viz. that he is something that
actually exists.
Locke Hum IV, 10, §2, pp. 619-620