DANCEST 805 Lecture Notes - Lecture 16: Modus Tollens, Modus Ponens, Propositional Calculus
Document Summary
Task 5 the sleep of reason produces monsters. Eysenck chapter 14: inductive & deductive reasoning. Nancy does not get wet conclusion: it is not raining. Modus tollens is valid but is often regarded as invalid. People consistently perform much better with modus ponens than modus tollens: affirmation of the consequence, denial of the antecedent: Premises: if it is raining, then nancy gets wet. Conclusion: therefore, nancy does not get wet. Conclusion is invalid in terms of traditional logic, e. g. nancy could have taken a shower to get wet. Contextual information irrelevant to the validity of the conclusion nevertheless influences judgements of conclusion validity. 1 conditional reasoning is strongly influenced by the availability of knowledge in the form of counterexamples appearing to invalidate a given conclusion the number of available counterexamples had a major impact on performance. There are important individual differences in the strategies used by participants involves hypothesis testing using a conditional rule rather than a pure deductive-reasoning task.
