formal logic

Aristotle’s Theses in Propositional Logic

Aristotle's theses, specifically ¬(¬A → A) and ¬(A → ¬A), are key formulas in propositional logic. They are theorems in…

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Aristotelian Logic

Aristotle's traditional logic, a foundational system in Western thought, centers on syllogisms and the principle of non-contradiction. It provides a…

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Aristotelian Comprehension Schema

The Aristotelian comprehension schema, represented as (∃x)Φ → (∃Y)(∀x)(Yx ↔ Φ) in second-order logic, defines the existence of a property…

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Antilogism: Understanding Logical Contradictions

An antilogism is a syllogism with three premises that lead to a contradiction. It demonstrates the inconsistency of the initial…

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Anti-extension in Set Theory and Logic

The anti-extension of a concept or predicate includes all objects that do not fall under its definition. It's the complement…

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Alethic Modal Logic

Alethic modal logic explores modalities of truth, focusing on concepts like necessity and possibility. It provides a formal framework for…

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Affirming the Consequent Fallacy

A logical fallacy where an argument incorrectly assumes the antecedent is true because the consequent is true. It's a common…

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Affirmative Proposition

An affirmative proposition asserts the truth of a statement, affirming a quality or relation. It contrasts with a negative proposition,…

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Addition Rule of Inference in Formal Logic

The addition rule in formal logic allows inferring a disjunction from a single proposition. It states that if P is…

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Accessibility Relation in Modal Logic

An accessibility relation in modal logic defines the connections between possible worlds in a model. It dictates which worlds are…

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