Ramsey's Test, Adams' Thesis, and Left-nested Conditionals

SPEAKER

Richard Dietz

ABSTRACT

Ernest Adams famously suggested that the acceptability of any indicative con-
ditional whose antecedent and consequent are both factive sentences amounts
to the subjective conditional probability of the consequent given the antecedent.
The received view has it that this thesis offers an adequate partial explication
of Ramsey’s test, which characterises graded acceptability for conditionals in
terms of hypothetical updates on the antecedent. Indeed, some results in van
Fraassen [1976] may raise hope that this explicatory approach to Ramsey’s test
is extendible to left-nested conditionals, that is, conditionals whose antecedent
is itself conditional in form. We argue that this interpretation of van Fraassen’s
results results is rejectable. In effect, we provide an argument against a gener-
alisation of Adams’ thesis for left-nested conditionals from material inadequacy.