(1) The first of these, with which alone the argument is primarily concerned, is hardly discussed
on its own account except in the final passage with which we have just been concerned. Here it
is argued that comparison, knowledge of existence, and understanding of number, are essential
to knowledge, but cannot be included in perception since they are not effected through any
sense-organ. The things to be said about these are different. Let us begin with likeness and
unlikeness.
That two shades of colour, both of which I am seeing, are similar or dissimilar as the case may
be, is something which I, for my part, should accept, not indeed as a "percept," but as a
"judgement of perception." A percept, I should say, is not knowledge, but merely something
that happens, and that belongs equally to the world of physics and to the world of psychology.
We naturally think of perception, as Plato does, as a relation between a percipient and an object:
we say "I see a table." But here "I" and "table" are logical constructions. The core of crude
occurrence is merely certain patches of colour. These are associated with images of touch, they
may cause words, and they may become a source of memories. The percept as filled out with
images of touch becomes an "object," which is supposed physical; the percept as filled out with
words and memories becomes a "perception," which is part of a "subject" and is considered
mental. The percept is just an occurrence, and neither true nor false; the percept as filled out
with words is a judgement, and capable of truth or falsehood. This