Isaac Newton’s ‘De gravitatione et aequipondio fluidorum’: its purpose in historical context

Few texts in the history of science and philosophy have achieved the level of interpretative indeterminacy as a short manuscript tract by Isaac Newton, known as ‘De gravitatione’. On the basis of some new evidence, this article argues that it is an introductory fragment of some lectures on hydrostatics delivered in the of spring 1671. Taking seriously the possibility of a pedagogical purpose, it is then argued that the famous digression on space, far from articulating a sophisticated metaphysics that may have owed something to Henry More, was a simple piece of mixed-mathematical prolegomena designed to facilitate the subsequent geometrical argumentation. In this regard, Newton was doing the same as his mentor, Isaac Barrow, had done in his own mathematical lectures; both drew heavily on the explicitly anti-metaphysical approach of Pierre Gassendi. It is shown that More himself would have almost certainly opposed Newton’s approach. The excesses of metaphysical readings of Newton’s intentions are challenged; there is no warrant for reading the digression as directly relevant to the Principia.