Polysyllogism a series of syllogisms connected by the fact that the conclusion of one syllogism becomes a premise of another. The syllogism whose conclusion is used as a premise in another syllogism within the chain is called the prosyllogism; the syllogism is which the conclusion of another syllogism within the chain is used as a premise is called the episyllogism. To illustrate, take the standard form of the simplest polysyllogism: (a) (1) Every B is A (2) Every C is B (3) , Every C is A (b) (4) Every C is A (5) Every D is C (6) , Every D is A. The first member (a) of this polysyllogism is the prosyllogism, since its conclusion, (3), occurs as a premise, (4), in the second argument. This second member, (b), is the episyllogism, since it employs as one of its premises (4) the conclusion (3) of the first syllogism. It should be noted that the terms ‘prosyllogism’ and ‘episyllogism’ are correlative terms. Moreover, a polysyllogism may have more than two members. See also SYLLOGIS. I.Bo.