ABSTRACT
Once we have made an inference, what do we do with it? Our inferred beliefs are guides to action that help us to get what we want and avoid trouble. Less practically, we also sometimes infer simply because we want to learn more about the way the world is. Often, however, we are not satisfied to discover that something is the case: we want to know why. Thus our inferences may be used to provide explanations, and they may themselves be explained. The central question about our explanatory practices can be construed in several ways. We may ask what principles we use to distinguish between a good explanation, a bad explanation, and no explanation at all. Or we may ask what relation is required between two things to count one to be an explanation of the other. We can also formulate the question in terms of the relationship between knowledge and understanding. Typically, someone who asks why something is the case already knows that it is the case. The person who asks why the sky is blue knows that it is blue, but does not yet understand why. The question about explanation can then be put this way: What has to be added to knowledge to get understanding? As in the case of inference, explanation raises problems both of justifi cation and of description. The problem of justification can be understood in various ways. It may be seen as the problem of showing whether things we take to be good explanations really are, whether they really provide understanding. The issue here, to distinguish it from the case of inference, is not whether there is any reason to believe that our putative explanations are themselves true, but whether, granting that they are true, they really explain. There is no argument against the possibility of explanation on a par with Hume's argument against induction. The closest thing is regress of why. The why-regress is a feature of the logic of explanation that many of us discovered as children, to our parents’ cost. I vividly recall the moment it dawned on me that, whatever my mother's answer to my latest why-question, I could simply retort by asking ‘Why?’ of the answer itself, until my mother ran out of answers or patience. But if only something that is itself understood can be used to explain, and understanding only comes through being explained by something else, then the infinite chain of why's makes explanation impossible. Sooner or later, we get back to something unexplained, which ruins all the attempts to explain that are built upon it (cf. Friedman,1974, pp. 18–19).
