Aristotle
(384-322 BC):
Greek philosopher.
Syllogism: As defined by Aristotle, the founder of the traditional formal logic, a 'discourse in which, certain things being stated, something other than what is stated follows of necessity from their being so'.
The propostions of a categorical syllogism must between them employ exactly three terms, each term appearing twice, as for example, in 'All men are mortal, and no gods are mortal, therefore no men are gods.'
A Dictionary Of Philosophy. Second edition. (Pan Books 1984)