 In this way, Locke held the common view that Newton’s theory of universal gravity was incompatible with the mechanical philosophy—and perhaps, unintelligible to us for that very reason—and when forced to choose between these two options, he evidently sided with Newton, thinking that his theory was supported by “experience”. He did so by endorsing the view that God must have added “powers” or “ways of operations” to material bodies that cannot be derived from our idea of body. Such powers or ways of operations would in this case result in gravitational interactions, presumably amongst bodies that are spatially separated from one another by great distances. Yet from Locke’s point of view, the fact that Newton’s theory convinces him that such powers exist does not entail that that theory renders gravity “conceivable”: even if the theory of universal gravity is correct, it does not allow us to understand how matter—what Locke would call “extended solid substance”—can interact gravitationally with other matter when the bits of matter are not in contact with one another (Downing 1997). So Locke has concluded that bodies can operate on one another through some means other than impulse, but he retains his firmly held belief that any such operation is not intelligible to us. Locke accepted the conclusion that spatially separated bodies causally interact with one another in accordance with the law of universal gravitation, but concluded that the law itself did not render that causal interaction intelligible. This is precisely the kind of reaction to Newton’s theory of universal gravity bemoaned by Leibniz, who would argue that any operations or powers attributed to material bodies must meet the basic criterion of intelligibility established by the mechanist approach; he might also be inclined to argue that any laws regarded as governing the interactions of bodies must also meet that criterion by being derivable in some way from our basic concept of matter (see below). Regardless, this is an excellent example of a case in which Newton’s theory in the Principia had a direct impact on the development of philosophical views of causation in the late seventeenth century.