 The commitment to careful observation and description of phenomena as the starting point of science, and then the success at explaining and accounting for observed phenomena through the method of induction, naturally leads to the development of new sciences for new domains in the Enlightenment. Many of the human and social sciences have their origins in the eighteenth century (e.g., history, anthropology, aesthetics, psychology, economics, even sociology), though most are only formally established as autonomous disciplines later. The emergence of new sciences is aided by the development of new scientific tools, such as models for probabilistic reasoning, a kind of reasoning that gains new respect and application in the period. Despite the multiplication of sciences in the period, the ideal remains to comprehend the diversity of our scientific knowledge as a unified system of science; however, this ideal of unity is generally taken as regulative, as an ideal to emerge in the ever-receding end-state of science, rather than as enforced from the beginning by regimenting science under a priori principles.