Philosophy I / The Language of Propositional Logic
Practice question · Numerical answer

A conditional fails only when it promises something and does not deliver. In how many of the four assignments of truth values to PP and QQ is PQP \rightarrow Q false?

Hints
  1. A conditional fails only when its antecedent holds and its consequent does not.
  2. That is one row out of four.
Show the answer

1

Why

Exactly one: PP true with QQ false. In the other three rows the conditional is true, including both rows where PP is false, which is the result that surprises people.

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