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Perceptual indiscriminability : in defence of Wright's proof
The Philosophical Quarterly
  • Rafael DE CLERCQ, University of Leuven, Belgium; Fund for Scientific Research-Flanders
  • Leon HORSTEN, University of Leuven, Belgium
Document Type
Journal article
Publication Date
Oxford University Press

A series of unnoticeably small changes in an observable property may add up to a noticeable change. Crispin Wright has used this fact to prove that perceptual indiscriminability is a non-transitive relation. Delia Graff has recently argued that there is a 'tension' between Wright's assumptions. But Graff has misunderstood one of these, that 'phenomenal continua' are possible; and the other, that our powers of discrimination are finite, is sound. If the first assumption is properly understood, it is not in tension with but is actually implied by the second, given a plausible physical assumption.

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De Clercq, R., & Horsten, L. (2007). Perceptual indiscriminability: in defence of Wright's proof. The Philosophical Quarterly, 54(216), 439-444. doi: 10.1111/j.0031-8094.2004.00364.x