Knowledge, concept of

DOI: 10.4324/9780415249126-P031-1
Version: v1,  Published online: 1998
Retrieved June 21, 2021, from

2. Propositional knowledge is not mere true belief

Propositional knowledge is a species of belief; but which beliefs are knowledge? The first thing to note is that a belief must be true in order for it to count as knowledge. But that is obviously not enough. First, true beliefs can be based upon faulty reasoning. Suppose that I believe that smoking is a leading cause of fatal lung cancer because I infer it from the fact that I know two smokers who died of lung cancer. The generalization is true, but my evidence is too meagre for my belief to count as knowledge. Second, true beliefs can be based on false beliefs. Modifying an example used by Bertrand Russell, suppose that I believe truly that the last name of the President of the United States in 1996 begins with a ‘C’. Also suppose this belief is based upon the false belief that the President is Winston Churchill. My true belief that the President’s name begins with a ‘C’ is not knowledge because it is based on a false belief.

Third, even some true beliefs resulting from good reasoning based upon true beliefs are not knowledge. Suppose that I believe (truly) that my neighbours are at home. My belief is based upon good reasoning from my true belief that I see lights on and that, in the past, the lights have been on only when they were at home. But suppose further that this time the lights were turned on by a guest and that my neighbours had just entered the house and would not have had time to turn on the lights. In this case, I fail to know that my neighbours are home. So, the central question becomes: what must be added to true belief to convert it into knowledge?

Citing this article:
Klein, Peter D.. Propositional knowledge is not mere true belief. Knowledge, concept of, 1998, doi:10.4324/9780415249126-P031-1. Routledge Encyclopedia of Philosophy, Taylor and Francis,
Copyright © 1998-2021 Routledge.

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