A. C. Crombie on Aristotle

“According to Aristotle, scientific investigation and explanation was a twofold process, the first inductive and the second deductive. The investigator must begin with what was prior in the order of knowing, that is, with the facts observed through the senses, and he must ascend through induction to generalizations or universal forms or causes which were most remote from sensory experience, yet causing that experience and therefore prior in the order of nature. [Footnote:] The idea that the order of demonstration was the order of nature came from Plato. Aristotle said that the order of discovery was the reverse of the order of demonstration.”

“The model of scientific knowledge, in which effects could be shown to follow necessarily from their causes as conclusions from premises, Aristotle held to be mathematics, and where mathematics could be used in the natural sciences their conclusions were also exact and necessary. ... Of the inductive process by which the investigator passed from sensory experience of particular facts or connexions to a grasp of the prior demonstrative principles that explained them, Aristotle gave a clear psychological account. The final stage in the process was the sudden act by which the intuitive reason or νοῦς, after a number of experiences of facts, grasped the universal or theory explaining them, or penetrated to knowledge of the substance causing and connecting them.”