The word “discrimination” is popularly used in two senses (1) we speak
of a man having “good discrimination,” meaning by that a sort of good
judgment. (2) Discrimination, in the psychological sense, however,
means the noticing of any part of an object, as distinct from the whole.
All sensations tend to fuse and become a single compound;
discrimination singles these out, and separates them. Such differences
may be felt, if they are _really_ different, and different _enough_;
further, they must fall more or less in succession upon the same organ,
and not simultaneously. If they do, they are apt to blend hopelessly.
Especially is this the case if the elements of the impression have
never been experienced singly before. If we are familiar with a thing,
we can begin to discriminate the elements going to compose it. It is,
however, true that only such elements as we are acquainted with, and
can imagine separately, can be discriminated, within a total sense
impression. If a thing be associated at one time with one thing and
at another time with another, this may become a separate “thing” for
the mind, which singles it out, by an act of discrimination, and places
it in a position by itself. Such acts of discrimination may be greatly
improved by practice.