In his wonderful paper, "Indicative Conditionals", (which I have recently reread because of a great paper on it by Fabrizio Cariani) Stalnaker presents a theory that allows him to maintain a unified semantics of the ordinary-language conditional, that is, without having one semantics (broadly construed) for so-called indicative conditionals like 'if it's raining, the streets are wet' and another for so-called subjunctive conditionals (aka 'counterfactuals') like 'if it were raining, the streets would be wet'. I want to challenge his maneuver here, and I want to suggest that any maneuver won't work, either. In an important sense, supposition is too powerful an attitude; there are too few restrictions on what we may suppose, and thus on what conditionals we may assert.
In my last post, I introduced a principle, Clarity, which is that we ought not to have unclear beliefs. I then tried to define when a belief is unclear. Roughly, what I said there was that a person S's belief is unclear if S doesn't know what it rationalizes or it is rationalized by. In this post, I'm going to make that definition a little clearer, and then get a little further in actually justifying Clarity. (This post is readable without reading the first one.) I'll argue that unclear beliefs generate avoidable epistemic problems; since they are avoidable, we ought to avoid them; so we ought not to have unclear beliefs.