Epistemology

The root of the modern conception of nature lies in Descartes's idea that there are but two kinds of substance: spiritual substance (mind) and material substance (body). Since the essence of body is extension, and extension can be determined quantitatively, mathematics is the language of nature. The modern conception of nature departs from the Aristotelian-scholastic conception, which placed heavy emphasis on teleological explanation. According to this view, distinct principles determine the character or essence of different kinds of things in nature (or "natural kinds"); each kind of thing is driven, as it were, to express its "nature" according to its principle. In contrast, the modern mechanistic view deemphasizes the importance of determining natural kinds, focusing instead on universal laws of the motion of matter.

The natural philosopher Robert Boyle (1627–1691) and others charged that the Aristotelian framework was unable to yield satisfying explanations of natural phenomena. As Boyle developed his account, he advanced a hypothesis about minute particles of matter called "corpuscles": according to the "corpuscular philosophy," particular phenomena—including the appearance of qualities like color—can, in theory, be explained in terms of the arrangement and motion of these atoms. The theory of corpuscles was merely a hypothesis advanced on the recommendation of its explanatory power: "corpuscles" were theoretical entities, which had not been perceived even with the aid of instruments.