2. Knowledge is the perception of the agreement or disagreement of two ideas.
Knowledge then seems to me to be
nothing but the perception of the connexion of and agreement, or disagreement and repugnancy of any of our
ideas. In this alone it consists. Where this perception is, there is knowledge, and where it is not, there, though we
may fancy, guess, or believe, yet we always come short of knowledge. For when we know that white is not black,
what do we else but perceive, that these two ideas do not agree? When we possess ourselves with the utmost
security of the demonstration, that the three angles of a triangle are equal to two right ones, what do we more but
perceive, that equality to two right ones does necessarily agree to, and is inseparable from, the three angles of a
triangle?
