A discipline, at least to the initiated, is known more by the questions it asks than by the answers that it provides. For questions indicate goals or aspirations that answers may not reach. At certain periods, however, a field of knowledge may be more conspicuously characterized by the controversies that occur among those who work in it. When these take the form of debates over the adequacy of particular answers, as determined by agreed, even though sometimes imprecise, criteria of assessment, they are unlikely to be highly prominent, except for the immediate participants. When, on the other hand, such controversies extend to the standing of the questions asked and place in dispute the means of appraising answers, it becomes obvious to all that something is happening that has implications for the entire field. Clearly the discipline is undergoing redefinition or at least an attempt at redefinition that may sharply alter its meaning.