The impulse to study politics scientifically is both old and persistent. Aristotle collected 158 constitutions in order to generalize about events and institutions in the Politics. Early in the Renaissance, Machiavelli revived the Aristotelian program in the Discourses and The Prince, although he did not seem to have as clear a vision of the scientific method as did Aristotle. Late in the eighteenth century, when the term political science came into general use, John Adams studied republics in exactly the Aristotelian spirit and with, perhaps, an even bolder claim for political science:

By the twentieth century, however, hardly anyone shared Adams's faith in the relative certainty of social and physical science. Surely few people now believe that our laws of political life are as certain or as useful for making predictions as are the laws employed in sending a man to the moon or in eradicating smallpox. In 1778, however, when Adams started his book, electricity had been identified but hardly understood, chemistry consisted mainly of the story of phlogiston, and no one had ever thought that bacteria were connected with disease.