more from Fred Dretske

Single Idea 19544

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

Full Idea

Closure is the epistemological principle that if S knows that P is true and knows that P implies Q, then, evidentially speaking, this is enough for S to know that Q is true. Nothing more is needed.

Gist of Idea

Closure says if you know P, and also know P implies Q, then you must know Q


Fred Dretske (The Case against Closure (and reply) [2005], p.25)

Book Reference

'Contemporary Debates in Epistemology (2nd ed)', ed/tr. Steup/Turri/Sosa [Wiley Blackwell 2014], p.25

A Reaction

[Dretske was the first to raise this issue] It is 'closure' because it applies to every case of Q, which is every implication of P that is known. The issue is whether we really do know all such Qs. Dretske doubts it. See his zebra case.