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The study of categorical propositions reveals how inferences can be made conclusively.  If the form of an argument  is valid and the premisses are true, the conclusion  follows with absolute certainty.

Take some care with the logical relations called contrariety and subcontraiety.  For some persons, these inferences are initially counterintuitive.



Links to Lecture Notes…

  • Quantity, Quality, and Distribution
    The properties of standard form categorical propositions are explained and illustrated.
  • The Square of Opposition
    The logical relations of contradictory, contrariety, subcontrariety, and subalternation are explained and illustrated.
  • Futher Immediate Inferences
    The Square of Opposition is reviewed, and three additional inferences are explained and illustrated: conversion, obversion, and contraposition.
  • Successive Immediate Inferences
    The following exercises are taken from Irving M. Copi and Carl Cohen, Introduction to Logic
  • Strategies for Successive Inferences
    The technique of successive applications of logical relations drawn from the square of opposition and further immediate inferences is discussed and illustrated.
  • Ordinary Language Inferences
    Three ordinary language examples of using immediate inferences demonstrate the uses of standard form categorical propositions and their logical relations.

  • Venn Diagrams The technique of representing statements by means of pictures is explained.

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09.25.09       2004-9   Licensed under

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