2 NOTIONS OF EPISTEMIC VALIDITY - EPISTEMIC MODELS FOR RAMSEY CONDITIONALS

How to accept a conditional? F. P. Ramsey proposed the following test in (Ramsey 1990). 'If A, then B' must be accepted with respect to the current epistemic state iff the minimal hypothetical change of it need ed to accept A also requires accepting B. In this article we propose a formulation of (RT), which unlike some of its predecessors,(1) is com patible with our best theory of belief revision, the so-called AGM the ory (see (Gardenfors 1988), chapters 1-5 for a survey). The new test, which, we claim, encodes some of the crucial insights defended by F. P . Ramsey in (Ramsey 1990), is used to study the conditionals epistemic ally validated by the AGM postulates. Our notion of validity (PV) is c ompared with the notion of negative validity (NV) used by Gardenfors i n (Gardenfors 1988). It is observed that the notions of PV and NV will in general differ and that when these differences arise it is the not ion of PV that is preferable. Finally we compare our formulation of th e Ramsey test with a previous formulation offered by Gardenfors (GRT). We show that any attempt to interpret (GRT) as delivering acceptance conditions for Ramsey's conditionals is doomed to failure.