6 Modal and Anti-Luck Epistemology

this is a reading summary of the book “THE ROUTLEDGE COMPANION TO EPISTEMOLOGY”

It is a defense to the Gettier Problem, by adding extra requirements for JTB to be a knowledge: belief should be true “out of luck”.

The defense says, it is not the way Smith’s think that make the belief to be true.

What do you mean by good luck in Smith’s case?

Because the justification is not “connected” to the fact



  1. avails herself of sufficient relevant evidence,
  2. reasonably thorough reflective examination of evidence
  3. the evidence is appropriately connected to the fact
  4. forms a belief on the basis of evident


  1. justified in believing
  2. the justification is not appropriately connected to the fact
  3. is nevertheless true


Making sure the justification is appropriately connected! – Difficult (lottery case)

Because the belief is not connected to the fact


Duncan Pritchard

“A matter of luck that the agents’ belief is true”

Parallel universes, where the belief is not universally true.

Modal epistemology might say that a belief counts as knowledge only if it is true not only in the actual world, but also in a certain proportion of worlds.


How sufficient is a sufficient proportion?

Distinct way of giving expression to the anti-luck intuition

  • Sensitivity: whether or not the belief is true in fact is not ensured by the way Smith believes — in other words, whether the belief in his mind is sensitive to the truth
  • Safety: under some circumstance, his belief can be just false

Sensitivity Theories

Robert Nozick

test if one’s belief is sensitive to truth: considering the nearest possible world in which p is false, and consider if S still believes that p. Only sensitive belief could be knowledge

Robert Nozick (revised)

S knows that p iff:

  1. p is true
  2. S believes p via believe M
  3. if p weren’t true and S were to use M to infer that p is not true; and
  4. if p were true and S were to use M to infer that p is true.

Keith DeRose (argues)

Safety Theories

Even in the parallel universe of the same situation, Smith’s belief could be false due to some other reason.

Ernest Sosa

belief is safe iff: S would believe that p only if it were so that p


If S knows a contingent proposition, p , then if in most nearby possible worlds using the same way to form the belief, S believes that p only when p is true

(even stronger)

if S knows a contingent proposition, p, then in nearly all (if not all) nearby possible …


The difference between safety theory and sensitivity theory.

Safety theories and sensitivity theories are both moral epistemic theory to specify “how sufficient the proportion of the other world to have the connection of the belief/justification and the truth, that can made the belief knowledge”

But two theories work in different direction:

  • in sensitivity theories, they discussed the nearby worlds where the belief is false and analyses the justification of the protagonist in that case.
  • in safety theories, they discussed the (most of) nearby possible worlds where S still believes in p, and if the belief is still true in that case.

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