In assimilating the study of history to the study of natural science, Bacon emphasized the collection of historical facts and the need to induce general propositions from them. He indicated the psychological character of these propositions and claimed that historians were, and philosophers were not, competent to put moral and mental phenomena on a scientific basis. On the formal side, his theory of history was based on Aristotelian faculty psychology-history, the product of the mnemonic faculty, dealt with phenomena true to life. In intent, his theory was designed to reorient the study of moral philosophy away from rationalism toward an empirical or historical foundation and to emphasize involuntary as well as voluntary aspects of behavior.