Aristotle - Posterior Analytics

Posterior Analytics is the fourth of Aristotle's six texts on logic which are collectively known as the Organon («Instrument»). Posterior Analytics deals with demonstration, definition, and scientific knowledge. Demonstration is distinguished as a syllogism productive of scientific knowledge, while Definition is marked as the statement of a thing's nature, a statement of the meaning of the name, or of an equivalent nominal formula. (Introduction adapted from Wikipedia)