  There is also the question about gravity’s relation to body, for both thinkers a persistent source of controversy.[30] One point of clarity and consensus is that neither Locke nor Newton considers the power of gravitational attraction to be essential to matter.  Newton consistently denies that it is essential (for instance in his explanatory remarks following Rule 3 of the Principia) and Locke refers to it only as power superadded or endowed by God. Locke’s concept of superaddition is controversial of course, as noted earlier, but he does appear to embrace action at a distance in his letter to Stillingfleet. Newton’s writings contain no such dramatic pronouncements. So while a few commentators interpret Newton as accepting action at a distance, grounded either in a superadded property (Henry 1994) or in a relational quality of matter (Schliesser 2011), his more favorable remarks are at best indirect. Most commentators interpret him as at least having very grave misgivings about distant action, so perhaps Locke was wise to credit his change of heart about gravity to “Mr. Newton’s incomparable book”, rather than to Newton himself.