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QLDPhilosophy and ReasonQuick questions
Unit 3: Reason and formal logic
Quick questions on Validity and soundness in deductive argument: QCE Philosophy and Reason
5short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What are common valid forms?Show answer
QCAA expects you to recognise named valid forms. Using P, Q for propositions:
What is testing for validity by counterexample?Show answer
To show an argument is invalid, describe a possible situation (a counterexample) in which the premises are true and the conclusion false. For affirming the consequent:
What is q1?Show answer
Define validity and explain why a valid argument can still be unsound. [3 marks]
What is q2?Show answer
Identify the form and state whether it is valid: "If P then Q; not-P; therefore not-Q." [2 marks]
What is q3?Show answer
Give a counterexample showing that affirming the consequent is invalid. [3 marks]
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