Skills Hub

Examples of logic

This is an example of a valid argument:

John is a human
All humans have brains
Therefore, John has a brain

In contrast in an invalid argument the conclusion does not follow from the premises:

This is an example of an invalid argument:

John is a fast runner
John is a University of Sussex student
Therefore, all University of Sussex students are fast runners

In some circumstances, it may be that whilst the conclusion does not follow from the premises, the conclusion is still true. In such an instance the argument would be invalid, but the conclusion would be true.

This is an example of an invalid argument with a true conclusion:

All Seagulls are birds
Some birds fly
Therefore, all seagulls fly

Student thinking

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