Here Newton makes the crucial postulation of general laws, rather than Aristotelian
forms, as the explanation for the manifest phenomena that fit into the general principles
discovered by science. His rejection of Aristotelian qualities as ‘occult’ trades on an
ambiguity in the meaning of ‘occult’. If it is taken as meaning occult as opposed to
manifest––i.e. not directly observable, as opposed to observable–it is true that Aristotelian
qualities (of some kinds) and forms are taken to be occult. However, Newton seems in this
passage to be equating ‘occult’ with unknowable. This is just what Aristotelians deny; they
hold that the nature of unobservable qualities and forms can be inferred from observation,
and can once inferred serve as the basis for predictions of future observations. To make this
equation, one must establish that being unobservable means being unknowable. Neither
Newton nor Locke could consistently argue for this view, since both of them believed in
the existence of an immaterial God; only with Hume did the claim that knowledge is
restricted to observation, in the non-Aristotelian sense of ‘observation’ used by Locke, get
developed in a consistent philosophical framework.