COMPARISON is the act of carrying the mind from one object to another, in order
to discover some relation subsisting between them. The result of comparison is
knowledge, which the intellect apprehends, but the act is an exercise of
attention voluntarily directing the energy of the mind to a class of objects or
ideas, and attended by judgment. The result of comparison is a judgment.
Comparison may thus be regarded as the essential act of thought in all its
forms, more simple as well as more complex. The concept, e.g., is the result of
the comparison of individual phenomena, the judgment of that of concepts, and
the inference of that of judgments. The theorems of mathematics, e.g., are a
series of judgments arrived at by comparison, or viewing different quantities
and numbers in their relations.