Practice question · Put in order
Arrange these compounds so that each is true in strictly more of the four assignments than the one before it.
- P and not-P
- if P then P
- P and Q
- P or Q
Hints
- Count the rows of a four-row table in which each sentence comes out true.
- The counts are 0, 1, 3 and 4 respectively.
Show the answer
- P and not-P
- P and Q
- P or Q
- if P then P
Why
True in 0, 1, 3 and 4 rows respectively. Counting satisfying rows orders sentences by logical strength: a contradiction excludes everything, a tautology excludes nothing, and the informative sentences lie in between.
Practise The Language of Propositional Logic
The app has 4 more questions on this lesson, and keeps your place in the course. Philosophy I is free to start.
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