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Do You Know Everything That You Know?

Published online by Cambridge University Press:  01 January 2020

Steven R. Levy*
Affiliation:
University of California, Riverside

Extract

In the ongoing attempt to provide a satisfactory analysis of knowledge numerous conditions have been proposed as necessary and sufficient — the most noteworthy being justification, truth, and belief. In addition, various epistemic principles are frequently employed. In this paper I intend to show how the seemingly innocuous justification condition, along with two relatively uncontroversial epistemic principles, can give rise to a paradoxical situation.

Type
Research Article
Copyright
Copyright © The Authors 1979

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References

1 In Belief, Truth and Knowledge (Cambridge, 1973), p. 186.Google Scholar

2 Of course it may be rational for S to believe something that he does not, in fact, believe (perhaps he has never thought about it). So the satisfaction of the antecedent of [1) does not entail that S believes that (p & q … )-only that such a belief would be rational. Throughout this discussion we shall also make the usual additional assumptions required by epistemic principles such as [1): (1) that S understands the logical entailment between the components of a conjunction and the conjunction itself, (2) that S correctly deduces the conjunction as a result of his understanding of the entailment, and (3) that S believes the conjunction as a result of (1) and (2). At certain points in the discussion we shall stop short of making the third assumption for reasons that will become obvious.

3 See, e.g., Kyburg, H. E., Probability and the Logic of Rational Belief (Middletown, 1961).Google Scholar

4 Op. cit., p. 139.

5 A similar point was made by Goldman, Alan H., “A note on the conjunctivity of Knowledge,” Analysis (1975).CrossRefGoogle Scholar

6 Keith Lehrer makes a related observation in “When Rational Disagreement is Impossible,” Nous (1976).

7 With the supposition stated in this way, the counterexample works when modified so as to omit question 4 from the examination but to allow that S rationally believes that he does not know everything that he thinks he knows.

8 Op., cit.

9 See, for example, Goldman, Alvin, “Discrimination and Perceptual Knowledge,” journal of Philosophy (1976).CrossRefGoogle Scholar Goldman's analysis there is on the right track although it suffers because it contains a condition similar to a defeasibility requirement. I have examined such requirements in depth in “Defeasibility Theories of Knowledge,” Canadian journal of Philosophy (1977), and in “Misleading Defeaters,” The journal of Philosophy (1978).