Location of Repository

The paradox of idealization

By S. Florio and J. Murzi


A well-known proof by Alonzo Church, first published in 1963 by Frederic Fitch, purports to show that all truths are knowable only if all truths are known. This is the Paradox of Knowability. If we take it, quite plausibly,\ud that we are not omniscient, the proof appears to undermine metaphysical doctrines committed to the knowability of truth, such as semantic antirealism. Since its rediscovery by Hart and McGinn (1976), many solutions to the paradox have been offered. In this article, we present a new proof to the effect that not all truths are knowable, which rests on different assumptions from those of the original argument published by Fitch. We highlight the general form of the knowability paradoxes, and argue that anti-realists\ud who favour either an hierarchical or an intuitionistic approach to the Paradox of Knowability are confronted with a dilemma: they must either give up anti-realism or opt for a highly controversial interpretation of the principle that every truth is knowable

Topics: phil
Publisher: Oxford Journals
Year: 2009
OAI identifier: oai:eprints.bbk.ac.uk.oai2:3179

Suggested articles



  1. (1963). A logical analysis of some value concepts. doi
  2. (2008). Anonymous referee reports, on Fitch’s ‘A Definition of Value’. doi
  3. (2008). Fitch’s paradox and typing knowledge. Notre Dame doi
  4. (1982). Intuitionism disproved? doi
  5. (2000). Knowledge and its Limits. Oxford: Oxford University Press. audiences for their valuable feedback. doi
  6. (1976). Knowledge and necessity. doi
  7. (2008). Logical types in some arguments about knowability and belief. doi
  8. (1994). Reply to Prawitz. doi
  9. (2007). Reply to Wolfgang Künne.
  10. (1985). The paradox of knowability. doi
  11. (1978). Truth and Other Enigmas. doi
  12. (2001). Victor’s error. doi
  13. (1975). Wang’s paradox. doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.