Ideas from 'The Case against Closure (and reply)' by Fred Dretske [2005], by Theme Structure

[found in 'Contemporary Debates in Epistemology (2nd ed)' (ed/tr Steup/Turri/Sosa) [Wiley Blackwell 2014,978-0-470-67209-9]].

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13. Knowledge Criteria / A. Justification Problems / 2. Justification Challenges / c. Knowledge closure
Closure says if you know P, and also know P implies Q, then you must know Q
We needn't regret the implications of our regrets; regretting drinking too much implies the past is real
Knowing by visual perception is not the same as knowing by implication
Reasons for believing P may not transmit to its implication, Q
The only way to preserve our homely truths is to abandon closure
P may imply Q, but evidence for P doesn't imply evidence for Q, so closure fails
We know past events by memory, but we don't know the past is real (an implication) by memory