Something ‘Might ’ Might Mean (Excerpted)

What do we do with expressions of epistemic possibility? What are we trying to accomplish when we sincerely say, for example: (1) It might be raining. (2) He might have forgotten. (3) You might be dreaming. (4) The world might have popped into existence five minutes ago. I answer that the central function of such sentences is to raise possibilities, and I think this near truism should guide our analysis of them. But the near truism is nowhere close to being trivial, for two reasons. Philosophers, linguists, computer scientists, economists, and others have found that a particular hypothesis about assertion helps us make fruitful predictions about communication, action, and coordination. This hypothesis is that the central function of assertion is not to raise possibilities but, in a sense I’ll explain later, to rule them out (Stalnaker 1974, 1978). From this hypothesis and our near truism it follows that epistemic ‘might ’ statements are not assertions. This surprising result is the first reason why the near truism is not trivial. But though it is surprising, I think the conclusion that epistemic ‘might ’ statements are not assertions is wel-come. For as I argue, epistemic ‘might ’ statements have effects and norms that are quite unlike those characteristic of assertion. In brief, a speaker who assertively utters ‘It might be that φ ’ does not thereby commit herself to any claim about how the world is. Rather, she makes a hedged recommendation that her addressees not inadvertently rule out the possibility that φ. If this is right, then—independentl