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Single Idea 6445

[filed under theme 13. Knowledge Criteria / A. Justification Problems / 2. Justification Challenges / c. Knowledge closure ]

Full Idea

The 'Relevant Alternatives' theory of knowledge said the main ingredient that must be added to true belief to make knowledge is that one be in a position to rule out all the relevant alternatives to what one believes.

Gist of Idea

You have knowledge if you can rule out all the relevant alternatives to what you believe

Source

report of Fred Dretske (Epistemic Operators [1970]) by Keith DeRose - Intro: Responding to Skepticism §6

Book Ref

'Skepticism', ed/tr. DeRose,K /Warfield,Ted [OUP 1999], p.14

A Reaction

Dretske and Nozick are associated with this strategy. There will obviously be a problem in defining 'relevant'. Otherwise it sounds quite close to Plato's suggestion that we need true belief with 'logos'.

The 17 ideas with the same theme [are known implications of knowledge also known?]:

20769 Sphaerus he was not assenting to the presence of pomegranates, but that it was 'reasonable' [Sphaerus, by Diog. Laertius]
19544 Closure says if you know P, and also know P implies Q, then you must know Q [Dretske]
19545 We needn't regret the implications of our regrets; regretting drinking too much implies the past is real [Dretske]
19547 Reasons for believing P may not transmit to its implication, Q [Dretske]
19546 Knowing by visual perception is not the same as knowing by implication [Dretske]
19548 The only way to preserve our homely truths is to abandon closure [Dretske]
19549 P may imply Q, but evidence for P doesn't imply evidence for Q, so closure fails [Dretske]
19550 We know past events by memory, but we don't know the past is real (an implication) by memory [Dretske]
6445 You have knowledge if you can rule out all the relevant alternatives to what you believe [Dretske, by DeRose]
8817 Logical entailments are not always reasons for beliefs, because they may be irrelevant [Pollock]
19551 How can we know the heavyweight implications of normal knowledge? Must we distort 'knowledge'? [Hawthorne]
19552 We wouldn't know the logical implications of our knowledge if small risks added up to big risks [Hawthorne]
19554 Denying closure is denying we know P when we know P and Q, which is absurd in simple cases [Hawthorne]
19524 We don't have the capacity to know all the logical consequences of our beliefs [Conee/Feldman]
19499 We can have evidence for seeing a zebra, but no evidence for what is entailed by that [Pritchard,D]
19500 Favouring: an entailment will give better support for the first belief than reason to deny the second [Pritchard,D]
19502 Maybe knowledge just needs relevant discriminations among contrasting cases [Pritchard,D]