PHI 1101 Lecture Notes - Lecture 8: Syllogism, Venn Diagram, Socialized Medicine

• School: University of Ottawa
• Department: Philosophy
• Course: PHI 1101
• Professor: Sardar Hosseini

Document Summary

Common types of deductive arguments (1) argument based on mathematics: Example: mark has twice as many cats as susan. Susan has 3 cats; therefore, mark has 6 cats. (2) argument from definition: truth of conclusion is guaranteed by definition. Or, jackso(cid:374) is a liar; therefore, he does(cid:374)(cid:859)t tell the truth (3) sentential (propositional) deductive arguments: Disjunctive syllogism (ds) addition (add) (4) categorical syllogism: syllogism (two premised argument) with each statement starting (cid:449)ith (cid:862)all,(cid:863) (cid:862)so(cid:373)e,(cid:863) (cid:862)(cid:374)o(cid:374)e,(cid:863) or (cid:862)e(cid:448)ery. (cid:863) (cid:894)chapter 5(cid:895) In categorical reasoning the statements, or claims, of interest are categorical statements. Categorical statements make simple assertions about categories, or classes, of things. A categorical syllogism consists of three parts: Use venn diagram (circles) to evaluate the validity/invalidity of categorical syllogism. In order to evaluate a categorical syllogism we must evaluate each premise (major and minor) separately, and then see if they support the conclusion. A categorical claim (premise) contains two distinct categories.