The Distinction

When we disagree, we want our disagreements to be substantive. Substantive disagreements require agreement on what the disagreement is about, which in turn requires mutual understanding. Lack of mutual understanding comes from two kinds of defects: hidden differences in how the parties understand some expression, or hidden differences in what they take to be the context in which their views are presented. The former defects are eliminable in principle and manageable in practice; the latter are something between troublesome and hopeless. So it is important to see how to tell them apart. One thing seems clear – these defects fall on opposite sides of the divide between semantics and pragmatics. This is one reason that the divide matters. Let me elaborate. Suppose you say that the Evening Star is a star and I say it is not. Ideally, we know well enough what the world would have to be like for our respective views to be correct: if the shiniest celestial object visible in the sky just after sunset (discounting the Moon) is a sphere of hot gases radiating energy derived from thermonuclear reactions you are right; otherwise I am. If we agree about this much, our debate is certainly substantive. But things could be less then ideal and still good enough for mutual understanding. Perhaps we don’t both know which one of the shiny objects in the sky is the Evening Star, or what exactly makes one of those objects a star. Nonetheless, there is a clear sense in which we know what the world would have to be like for our views to be correct: if the Evening Star is a star you are right, if it isn’t I am. Putting it this way is somewhat perplexing, for the statement does not move beyond the