Abstract

There are two ways for a piece of data to confirm a theory. If the theory was designed to fit the data, we say that the theory accommodates the data. If not, we say that the theory predicts the data. Many philosophers argue that prediction typically confirms theories more strongly than otherwise similar instances of accommodation; others deny this and place accommodation on a par with prediction. This paper argues that, perhaps surprisingly, there is a respect in which accommodation is typically epistemically superior to prediction. More precisely, the fact that a theory T accommodates some data D is, under certain common conditions, a pro tanto reason to place more confidence in T than if T had been used to predict D under those same conditions. In some cases, this pro tanto advantage of accommodation may even outweigh whatever epistemic advantage there might be to prediction, making accommodation epistemically superior to prediction all things considered.