Dichotomy. A division into two members. In the same way
trichotomy is a division into three, and polytomy into many.
Dichotomy, however, is distinguished from the others by taking a part in
practical logic of some little importance.
It is always à priori
possible, it being an axiom that one thing and its negative constitute,
and therefore any one term and its negative denote, the universe. This
process of dichotomy by contradiction has been called the
abscissio infiniti. This phrase, however, is objectionable, for that
which is the subject of abscission cannot be infinite. Plato practised
this method, and it forms a leading feature in that of Ramus, by whose
followers it was carried to a pedantic extent.