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Explanations, Tests, Unity and Necessity

1980; Wiley; Volume: 14; Issue: 1 Linguagem: Inglês

10.2307/2214888

1468-0068

Clark Glymour,

Philosophy and History of Science

The fact that a scientific hypothesis explains a phenomenon is supposed to be a reason for believing the hypothesis, and, indeed, at least sometimes a special reason over and above considerations of empirical adequacy. 1 Copernicans may have claimed that their theory gave a more accurate accounting of the motions of the planets than did the traditional Ptolemaic astronomy, but the real weight of their argument came from the claim that, even if both systems could save the phenomena, the Copernican theory offered the better explanations.2 If explanation sometimes provides a special reason for belief in a theory, over and above empirical adequacy, then explanations must, it seems, do something more to the phenomena, or say something more about the phenomena, than merely entail their description. My first question is what more it is that explanations do. There is no single answer because there is no single extra thing that explanations accomplish; shortly, I will try to describe two of the things that I think some explanations do, and in virtue of which we give credence to theories: they eliminate contingency and they unify. Explanations are sometimes contrasted with tests. A phenomenon that a theory explains is not always counted as a test of the theory; no one is surprised to read criticisms of psychoanalysis, for example, which admit that the theory explains things, but denies that the things explained constitute tests of psychoanalytic hypotheses. A test of an hypothesis is at least some occurrence that could have been otherwise, and that, had it been otherwise, would have been reason not to believe the hypothesis. In this minimal sense of test, traditional confirmation theories -the theories we have from Carnap,3 from Hempel,4 and the many varieties of hypotheticodeductivism-are theories of testing. They differ, of course, in their assessment of the relations required between theory