PHI 1101 Chapter Notes - Chapter 6: Venn Diagram, Syllogism

• School: University of Ottawa
• Department: Philosophy
• Course: PHI 1101
• Professor: Mark Brown

Document Summary

In categorical reasoning the statements, or claims, of interest are categorical statements. Categorical statements make simple assertions about categories, or classes, of things. Some business people are not moral. ": four standard forms of categorical statements: All s are p. (all cats are carnivores. ) No s are p. (no cats are carnivores. ) Some s are p. (some cats are carnivores. ) Some s are not p. (some cats are not carnivores. ) Some professors are not mean. ": a valid categorical syllogism is such that if its premises are true, then its conclusion must be true. We can check the validity of categorical syllogisms using the venn diagram method. Drawing a circle for each category or class in the argument, and diagramming the premises on these circles. If, after representing the premises, the conclusion is already represented on the diagram, then the argument is deductively valid. ". If the conclusion is not represented, then the argument is invalid.