It has often been assumed by advocates of the purist view of the theory of knowledge (a view outlined in Chapter 2) that John Locke was primarily an epistemologist with only a casual and superficial interest in the physical sciences. Despite the fact that he studied medicine and spoke glowingly of figures like Newton and Boyle,¹ Locke's Essay seems — at least on the surface — to be concerned with the epistemology of commonsense rather than with the logic and methods of science. Philosophers, evidently by reading history backwards, have written as if Locke accepted the view of Berkeley and Hume that the empiricist philosophy should not base itself on a 'scientific" metaphysics. Furthermore, in so far as the Essay does deal with scientific matters, it usually seems to treat them with derision and condescension. Consequently, some commentators have inferred that Locke was an opponent of the corpuscular micro-physics which dominated the science of his day and have viewed his Essay as an attempt to develop a theory of knowledge with no corpuscularian, or other quasi-scientific, bias. They suggest that Locke was opposed not only to the atomic hypothesis, but to the use of virtually all hypotheses about imperceptibles in science. Those commentators who do not explicitly attribute to Locke a hostility to hypotheses generally leave unmentioned his remarks about scientific method, as if philosophy of science was foreign to the spirit of the Essay.² Recently, however, Maurice Mandelbaum has pointed out riot only that Locke was sympathetic to the corpuscular program, but that an atomic view of nature is essential to Locke's epistemology and metaphysics.³ Rather than read Locke in the light of Berkeley's criticisms, Mandelbaum, urges us to approach the Essay with the atomic theories of Boyle and Newton in mind.