Purpose of Deductive Reasoning

1384 Words6 Pages
Deductive Reasoning & Decision Making Chapter 12 Complex Cognitive Tasks Deductive reasoning and decision making are complex cognitive tasks that are part of the thinking process. Thinking Problem Solving Deductive Reasoning Decision Making Deductive Reasoning 1 Deductive Reasoning Is a process of thinking in a logical way, where conclusion are drawn from the information given, for example: if there are clouds in the sky Information then it will rain. Conclusion Deductive Reasoning There are two kinds of deductive reasoning: 1. Conditional Reasoning 2. Syllogisms Conditional Reasoning Conditional reasoning (or propositional reasoning), tells us about the relationship between conditions. Conditional reasoning consists of true ifthen statements, used to deduce a true conclusion. Though the premises may be true the conclusions can be valid or invalid. 2 Valid Conclusion If a student is in cognitive psychology, Then she must have completed her general psychology requirements. Jenna is in cognitive psychology class Premises Conclusion Observation So Jenna must have completed her general psychology requirements. Valid Conclusion If a student is in cognitive psychology, Then she must have completed her general psychology requirements. David has NOT completed his general psychology requirements. Premises Conclusion Observation So David must NOT be in cognitive psychology class. Valid Conclusions Affirming If p is true then q is true the p is true antecedent q is true Modus ponens Valid If Newton was a scientist, then he was a person Newton was a scientist Newton was a person If p is true then q is true Denying the q is not true consequent p must be not true Modus tollens Valid If an officer is a general, then he was a captain. Gerald is NOT a captain, So he NOT a general. 3 Invalid Conclusions Affirming
Open Document