Dichotomy

Dichotomy, (from Greek dicha, “apart,” and tomos, “cutting”), a form of logical division consisting of the separation of a class into two subclasses, one of which has and the other has not a certain quality or attribute. Men thus may be divided into professional men and men who are not professionals; each of these may be subdivided similarly. On the principle of contradiction this division is both exhaustive and exclusive; there can be no overlapping,...