Build a practical foundation in formal and informal logic by translating propositions, testing categorical and hypothetical syllogisms, tracing immediate inferences, diagramming arguments, and diagnosing recurring fallacies.
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Identify subjects, predicates, copulas, quantity, quality, and complemented terms when representing ordinary statements in categorical form.
Use conversion, contraposition, obversion, distribution, and the square of opposition to evaluate relationships between propositions.
Apply constitutive and inferential rules to distinguish well-formed valid syllogisms from malformed or invalid arguments.
Distinguish valid conditional, disjunctive, and conjunctive patterns from errors such as affirming the consequent and denying the antecedent.
Diagram conclusions, independent or conjoint premises, nested subarguments, objections, and rebuttals to clarify evidential structure.
Recognize formal and informal fallacies involving ambiguity, relevance, causation, generalization, presupposition, false alternatives, and misplaced burdens of proof.
This course develops a systematic approach to analyzing arguments, moving from the language of categorical propositions to formal and informal patterns of inference. It begins with quantity, quality, complements, translation, and the distinction between truth and validity, then uses conversion, contraposition, obversion, distribution, and the square of opposition to examine relationships among propositions. From these foundations, the course develops procedures for evaluating and constructing categorical syllogisms through rules governing terms, premises, quality, quantity, and distribution. Conditional, disjunctive, and conjunctive reasoning extend the analysis to hypothetical syllogisms, special syllogistic forms, and dilemmas. The final lessons turn to everyday argumentation, showing how diagrams reveal conclusions, supporting premises, subarguments, and rebuttals. Throughout, worked examples and recurring fallacies demonstrate how structural analysis can uncover errors that semantic complexity, ambiguity, controversy, or intuitive judgment may conceal.
Professor Emeritus of Philosophy · University College Dublin
Gerard Casey is an Irish philosopher and author known for his work in political philosophy, philosophy of law, philosophy of religion, and libertarian thought.
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