“To arrive at some understanding of what is going on is hard
enough,” said Abraham Kaplan, “without having also to meet the
demand that we anticipate what will happen next” (1964, 351).
Political scientists have been taught to describe and to explain phenomena
rather than to predict them. Kaplan, for one, appeared to think that this
was enough. But within the rich soil of explanation, Kaplan admitted
(346), lay the seed of prediction. Indeed, Carl G. Hempel and Paul
Oppenheim (1948, 138), whom Kaplan took to task for saying so, flatly
stated that “an explanation is not fully adequate” unless it
also served as the basis for prediction (quoted in Kaplan, 346).