ABSTRACT
A particular version of the mechanistic hypothesis—namely, the idea that the body is a mechanism, was successfully exploited by Johannes Kepler to explain the workings of the eye. On extension, the mechanistic hypothesis would clarify the right kinds of questions to ask of the senses and perception—answerable physical questions as opposed to unanswerable metaphysical questions. The mechanistic hypothesis fashioned in the 17th century presented, therefore, a curious mix for future students of perception and action. Before proceeding further, perhaps we should adopt a more circumspect perspective on the central ideas that shaped the thinking of the era in which the mechanistic hypothesis arose. Circumspection is also called for in respect to another cornerstone of the mechanistic hypothesis, the division between primary properties as the topic of physical science and secondary properties as the topic of a very different form of inquiry.
