The beginnings of the social sciences in the 18th century are reflected in the grand encyclopedia of Diderot, with articles from Jean-Jacques Rousseau and other pioneers. The growth of the social sciences is also reflected in other specialized encyclopedias. The modern period saw ""social science"" first used as a distinct conceptual field. Social science was influenced by positivism, focusing on knowledge based on actual positive sense experience and avoiding the negative; metaphysical speculation was avoided. Auguste Comte used the term ""science sociale"" to describe the field, taken from the ideas of Charles Fourier; Comte also referred to the field as "social physics".