Many classifications of the sciences have been made from the time of Francis Bacon. Bacon's classification is based on the known faculties: 1) memory, 2) reason and 3) fantasy. Memory produces history (sacred, civil and natural). Reason leads to science itself, which covers: a) natural theology, b) the sciences of nature (which, in turn, subdivide into metaphysics or the study of formal and final causes), and c) the sciences of man (which are subdivided into a) logic or science of reason, b) ethics or science of the will and c) science of society). Fantasy reveals itself in poetry.