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Full Idea
A way of knowing there are cookies in the jar - visual perception - is not a way of knowing what one knows to be implied by this - that visual appearances are not misleading.
Gist of Idea
Knowing by visual perception is not the same as knowing by implication
Source
Fred Dretske (The Case against Closure (and reply) [2005], p.29)
Book Ref
'Contemporary Debates in Epistemology (2nd ed)', ed/tr. Steup/Turri/Sosa [Wiley Blackwell 2014], p.29
A Reaction
Why is the 'way of knowing' relevant? Isn't the only question that of whether implication of a truth is in infallible route to a truth (modus ponens)? If you know THAT it is true, then you must believe it, and implication is top quality justification. No?
| 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] |