Abstract
The main topic of this paper is one of the fraquently debated problems in comparative resesarch methodology; is it possible to draw longitudinal inferences from cross-sectional comparisons? The author attempts to answer it with particular reference to S.M. Lipset's Economic Development Hypothesis on democratizatoin. The hypothesis that "wealth fosters democracy", which was put forth inthe late 1950s, has survived increasingly statistical tests drawing mainly on cross-sectional data. After reviewing the contour of this hypothesis, the manner in which it is characterized by the inference from cross-sectonal, synchronic to longitudinal, diachronic generalization is explaines. Then, it id demonstrated how the "developmental equivalence" assumption is explained. Then, it is demonstrated how the "developmental equivalence" assumption is at the basis of this inference, and why without the assumption it cannot be made. However, is the assumption cannot be easily accepted. For answering this question, historical informations and diachronic propositions are needed. And so, lastly, the author proposes the methodological tasks to be done in order not to fall into the "cross-sectional fallacy".
