Knowledge Economics

Faites comme si je ne le savais pas.

In my youth it was said that what was too silly to be said may be sung. In modern economics it may be put into mathematics.

Various attempts have been made in recent years to state necessary and sufficient conditions for someone's knowing a given proposition. The attempts have often been such that they can be stated in a form similar to the following:
(a) S knows that P IFF (i) P is true, (ii) S believes that P, and (iii) S is justified in believing that P.
... These ... examples show that definition (a) does not state a sufficient condition for someone's knowing a given proposition.