PSY4313, Chapter 12: Deductive Reasoning and Decision Making

deductive reasoning

begin with some specific premises that are generally true, and you need to judge whether those premises allow you to draw conclusion based on the principles of logic

conditional (or propositional) reasoning task

one of the most common kinds of deductive reasoning which describes the relationship between condition; if…then structure; judge whether valid or invalid

syllogism

consists of two statements assumed to be true, plus a conclusion; refer to quantities and uses “all, none, or some”; judge whether valid, invalid, or indeterminate

propositional calculus

a system for categorizing four kinds of reasoning used in analyzing propositions or statements

antecedent

first proposition or statement; “if… part”

consequent

second proposition or statement; “then… part”

affirming

saying that the statement is true

denying

saying that the statement is false

affirming the antecedent

“if… part” of the statement is true; conclusion is valid; A → B conditional

affirming the consequent

“then… part” of the statement is true; conclusion is invalid, B → A converse

denying the antecedent

“if… part” of the statement is false; conclusion is invalid; ~A → ~B inverse

denying the consequent

“then… part” of the statement is false; conclusion is invalid; ~B → ~A contrapositive