Day 5: Indefeasibility Analyses of Knowledge

•     A Simple Indefeasibility Analysis of Knowledge

•     Problems with a Simple Indefeasibility Analysis

•     John Pollock’s Analysis

•     More Reading (Optional)

•     The Meno

•     Please Read IE 77-86

A Simple Indefeasibility Analysis of Knowledge

•      S knows that p at t₁ iff

   (i)   p is true;

   (ii)  S believes that p at t₁;

   (iii) p is evident to S at t₁;

   (iv)  there is no true proposition such that if it became evident to S at t₁, p would no longer be evident to S.

From “A Proposed Definition of Propositional Knowledge,” The Journal of Philosophy 68, 16 (1971), pp. 471-482.

Problems with a Simple Indefeasibility Analysis

•    What are the problems with Klein’s account?

•    Will making the indefeasibility condition more sophisticated solve the problem?

John Pollock’s Analysis

•     What is ultimate indefeasibility?

•     Do we need to be aware of defeaters that are themselves defeated?

•     Concerns

More Reading (Optional)

•      Crumely makes useful suggestions for more reading in the text.  Some other sources:

•      Useful introductory readings on indefeasibility and knowledge:

–    K. Lehrer and T. Paxson (“Knowledge: Undefeated Justified True Belief,” Journal of Philosophy, 1969);

–    R. Chisholm (Theory of Knowledge, 3^rd edition, 1989),

–    J. Pollock (Contemporary Theories of Knowledge 1^st edition 1987; 2^nd edition with L. Cruz 1999).  Pollock has more sophisticated work related to AI; see the instructor if you are interested in that sort of thing

•      Fred Dretske (“Conclusive Reasons,” Australasian Journal of Philosophy, 1971) provides a modal analysis of conclusive (undefeatable) reasons in knowledge (a kind of reliable indicator account of reasons that can’t be defeated)

The Meno

•    What is “tied down” true opinion that never leaves you once you have it?

•    A psychologistic reading

•    An epistemic reading

•    A mixed reading?