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DOI: 10.4324/9780415249126-P005-1
Version: v1,  Published online: 1998
Retrieved March 17, 2018, from

Article Summary

‘Certainty’ is not a univocal term. It is predicated of people, and it is predicated of propositions. When certainty is predicated of a person, as in ‘Sally is certain that she parked her car in lot 359’, we are ascribing an attitude to Sally. We can say that a person, S, is psychologically certain of a proposition, p, just in case S believes p without any doubts. In general, psychological certainty has not been a topic which philosophers have found problematic.

On the other hand, certainty as a property of propositions, as in ‘The proposition that Sally parked her car in lot 359 is certain for Sally’, has been discussed widely by philosophers. Roughly, we can say that a proposition, p, is propositionally certain for a person, S, just in case S is fully warranted in believing that p and there are no legitimate grounds whatsoever to doubt that p. The philosophical issue, of course, is whether there are any such propositions and, if so, what makes them certain.

Citing this article:
Klein, Peter D.. Certainty, 1998, doi:10.4324/9780415249126-P005-1. Routledge Encyclopedia of Philosophy, Taylor and Francis,
Copyright © 1998-2018 Routledge.

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