Full Idea
If two people are arguing 'If p, will q?' and are both in doubt as to p, they are adding p hypothetically to their stock of knowledge, and arguing on that basis about q; ...they are fixing their degrees of belief in q given p.
Gist of Idea
Asking 'If p, will q?' when p is uncertain, then first add p hypothetically to your knowledge
Source
Frank P. Ramsey (Law and Causality [1928], B 155 n)
Book Reference
Ramsey,Frank: 'Philosophical Papers', ed/tr. Mellor,D.H. [CUP 1990], p.155
A Reaction
This has become famous as the 'Ramsey Test'. Bennett emphasises that he is not saying that you should actually believe p - you are just trying it for size. The presupposition approach to conditionals seems attractive. Edgington likes 'degrees'.