[[Aristotle]] was the first to formalize the practice of reasoning. In particular, Aristotle developed a formalization of the [[Syllogism|categorical syllogism]], the three laws of logic, and the Square of Opposition. While modus ponens and its complement modus tollens were known to the medieval philosophers, it is not clear when these central laws of deduction were first formalized. | [[Aristotle]] was the first to formalize the practice of reasoning. In particular, Aristotle developed a formalization of the [[Syllogism|categorical syllogism]], the three laws of logic, and the Square of Opposition. While modus ponens and its complement modus tollens were known to the medieval philosophers, it is not clear when these central laws of deduction were first formalized. |