PHI 1101 Study Guide - Midterm Guide: Classical Logic

• School: University of Ottawa
• Department: Philosophy
• Course: PHI 1101
• Professor: Laura Byrne

Document Summary

Arguments: logically strong (inductively strong; deductively valid, logically weak (inductively weak; deductively valid) Law of excluded middle/bivalence: every statement must either be true or false (nothing in the middle). If a pro positing is true, negation must be false. (vice versa) ex: Socrates is not a man (has to be false) Law of non-contradiction: it is impossible for a statement and its negation to be true at the same time (you can"t truthfully assert or deny that something is the case) ex: Sets: propositions can be combined in groups or sets. Consistency: a set of propositions (a group of statements) is only consistent if it is possible for all the statements can be true at the same time - do not contradict one another. (inconsistent is the opposite) Socrates is an olympian god: does not imply that all seances are in fact true (could all be false as long as the are consistent).