The success of historical demography in establishing through statistical means the existence of family limitation in the past demonstrates that the methods of the quantitative social sciences can explain some problems better than traditional historiographical tools. In this case no literary evidence was available, and even if evidence existed it would have been too distorted to be reliable. Such findings may help historians understand broader issues such as the origins of the Industrial Revolution. Historical demography also may provide clues about the revolutionary process in Western Europe. At the same time, the transition within demography itself from a "transversal" to a "longitudinal" style of analysis suggests that it is as important for the social scientist to become "historical" as it is for the historian to become "social-scientific."