Dichotomy

A dichotomy is any splitting of a whole into exactly two non-overlapping parts, meaning it is a procedure in which a whole is divided into two parts. It is a partition of a whole (or a set) into two parts (subsets) that are: Such a partition is also frequently called a bipartition.

From en.wikipedia.org - January 13, 2014 12:58 PM
THE term of Dichotomy is used also when learning and teaching about Critical-Thinking, where one SHOULDN'T see ONLY BLACK & WHITE ;)