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In logic and mathematics, or, also known as logical disjunction or inclusive disjunction is a logical operator that results in true whenever one or more of its operands are true. In grammar, or is a coordinating conjunction.

Logical disjunction is an operation on two logical values, typically the values of two propositions, that produces a value of false if and only if both of its operands are false. More generally a disjunction is a logical formula that can have one or more literals separated only by ORs. A single literal is often considered to be a degenerate disjunction.

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Aristotle (Greek: Ἀριστοτέλης, Aristotélēs) (384 BC – 322 BC) was a Greek philosopher, a student of Plato and teacher of Alexander the Great. He wrote on many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, politics, government, ethics, biology and zoology.

Together with Plato and Socrates (Plato's teacher), Aristotle is one of the most important founding figures in Western philosophy. He was the first to create a comprehensive system of Western philosophy, encompassing morality and aesthetics, logic and science, politics and metaphysics. Aristotle's views on the physical sciences profoundly shaped medieval scholarship, and their influence extended well into the Renaissance, although they were ultimately replaced by Newtonian Physics. In the biological sciences, some of his observations were confirmed to be accurate only in the nineteenth century. His works contain the earliest known formal study of logic, which was incorporated in the late nineteenth century into modern formal logic. In metaphysics, Aristotelianism had a profound influence on philosophical and theological thinking in the Islamic and Jewish traditions in the Middle Ages, and it continues to influence Christian theology, especially Eastern Orthodox theology, and the scholastic tradition of the Roman Catholic Church. All aspects of Aristotle's philosophy continue to be the object of active academic study today.

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Did you know?

• ...that the Law of noncontradiction is the same as the Law of contradiction?
• ...that NAND alone or NOR alone make a functionally complete set of logical operators?
• ...that according to the continuum hypothesis, there is no cardinal number in between aleph null and the cardinality of the continuum?
• ...that all 24 valid syllogistic forms have names like 'Camestros' and 'Felapton'?
• ...that if a statement P implies another statement Q, and a third statement R also implies Q, and either P or R is true; then Q has to be true?
• ...that the dunce cap was named after a logician?
• ...that the collective noun for a group of logicians is a "sequitur of logicians"

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