Epistemological Skepticism, Semantic Blindness, and Competence-Based Performance Errors

Terry Horgan, Matjaž Potrč

Research output: Contribution to journalArticlepeer-review


The semantic blindness objection to contextualism challenges the view that there is no incompatibility between (i) denials of external-world knowledge in contexts where radical-deception scenarios are salient, and (ii) affirmations of external-world knowledge in contexts where such scenarios are not salient. Contextualism allegedly attributes a gross and implausible form of semantic incompetence in the use of the concept of knowledge to people who are otherwise quite competent in its use; this blindness supposedly consists in wrongly judging that there is genuine conflict between claims of type (i) and type (ii). We distinguish two broad versions of contextualism: relativistic-content contextualism and categorical-content contextualism. We argue that although the semantic blindness objection evidently is applicable to the former, it does not apply to the latter. We describe a subtle form of conflict between claims of types (i) and (ii), which we call différance-based affirmatory conflict. We argue that people confronted with radical-deception scenarios are prone to experience a form of semantic myopia (as we call it): a failure to distinguish between différance-based affirmatory conflict and outright inconsistency. Attributing such semantic myopia to people who are otherwise competent with the concept of knowledge explains the bafflement about knowledge-claims that so often arises when radical-deception scenarios are made salient. Such myopia is not some crude form of semantic blindness at all; rather, it is an understandable mistake grounded in semantic competence itself: what we call a competence-based performance error.

Original languageEnglish (US)
Pages (from-to)161-177
Number of pages17
JournalActa Analytica
Issue number2
StatePublished - Jun 2013


  • Cartesian scenarios
  • Categorical-content contextualism
  • Competence based performance errors
  • Différance based affirmatory conflict
  • Epistemic contextualism
  • Relativistic-content contextualism
  • Semantic blindness objection

ASJC Scopus subject areas

  • Philosophy


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