A problem for epistemology, which, if unanswered, opens one to epistemological skepticism. It seems like there are only three ways of completing a proof:

  • The circular argument, in which the proof of some proposition presupposes the truth of that very proposition
  • The regressive argument, in which each proof requires a further proof, ad infinitum
  • The dogmatic / foundationalist argument, which rests on accepted precepts which are merely asserted rather than defended.

These all tend to rub us the wrong way.

Addressing the trilemma

Changing the logic

This is a problem for classical logic in particular.

It could be addressed by introducing nonmonotonic logic: e.g. default and challenge approach to justification where some claims (e.g. first person observations) come with a default justification (which is not based on the justification of other claims). Yet they must be defended when challenged.

Challenging the meaning-theory distinction

The pervasive ideology of analyticity leads us to think that the meanings of our commitments are determined prior to deciding which claims are justified. Rejecting this is to say we cannot be clear about the contents of our expressions prior to determining their inferential realtions. So we cannot be in the original predicament we thought we were in.

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