Newton's Absolute Time

When Newton articulated the concept of absolute time in his treatise, Philosophae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy), along with its correlate, absolute space, he did not present it as anything controversial. Whereas his references to attraction are accompanied by the self- protective caveats that typically signal an expectation of censure, the Scholium following Principia’s definitions is free of such remarks, instead elaborating his ideas as clarifications of concepts that, in some manner, we already possess. This is not surprising. The germ of the concept emerged naturally from astronomers’ findings, and variants of it had already been formulated by other seventeenth century thinkers. Thus the novelty of Newton’s absolute time lay mainly in the use to which he put it

Force, matter, and metaphysics in Newton's natural philosophy

Metaphysical principles may be intuitively appealing by making the world intelligible, yet they are very difficult to justify. The role that such principles should play in the development of a physical theory becomes a pressing question for Newton, for he seeks a causal explanation of gravity that will eliminate the spectre of matter acting at distance, with sun and planets attracting one another across empty space. Does Newton reach an answer to his question about gravity's causal story, and if not, what stands in the way? Despite his empiricism, he is strongly drawn to the metaphysical principles that matter is passive and that causation is local, so at one level, his problem about gravity seems to be that of discovering some immaterial medium that might possess active powers. Yet I identify in Newton's reasoning a more fundamental problem about gravity, Newton's Substance Counting Problem. His ontology includes immaterial substances as well as material ones, and while his penchant for certain metaphysical principles keeps the search for an immaterial medium alive, his empiricism prevents him from postulating such a medium. He also allows, on empirical grounds, the possibility that substances of different kinds can co-occupy regions of space. Yet if two things can be in the same place at the same time, I argue, Newton has no empirical means of determining how many substances are present on the basis of perceived properties, or of associating those properties with one substance rather than another. Nor will he make those determinations by asserting the metaphysical principles he suspects to be true. Thus he has no means of associating active powers with an immaterial medium rather than with matter, and Newton's problem of discovering gravity's complete causal story is one that cannot be solved

Belief Contexts and Epistemic Possibility

Although epistemic possibility figures in several debates, those debates have had relatively little contact with one another. G. E. Moore focused squarely upon analyzing epistemic uses of the phrase, ‘It’s possible that p’, and in doing so he made two fundamental assumptions. First, he assumed that epistemic possibility statements always express the epistemic position of a community, as opposed to that of an individual speaker. Second, he assumed that all epistemic uses of ‘It’s possible that p’ are analyzable in terms of knowledge, not belief. A number of later theorists, including Keith DeRose, provide alternative accounts of epistemic possibility, while retaining Moore’s two assumptions. Neither assumption has been explicitly challenged, but Jaakko Hintikka’s analysis provides a basis for doing so. Drawing upon Hintikka’s analysis, I argue that some epistemic possibility statements express only the speaker’s individual epistemic state, and that contra DeRose, they are not degenerate community statements but a class in their own right. I further argue that some linguistic contexts are belief- rather than knowledge-based, and in such contexts, what is possible for a speaker depends not upon what she knows, but upon what she believes

Newton on Matter and Space in De gravitatione et aequipondio fluidorum

This paper explicates the concepts of matter and space that Newton develops in De gravitatione. As I interpret Newton’s account of created substances, bodies are constructed from qualities alone, as configured by God. Although regions of space and then “determined quantities of extension” appear to replace the Aristotelian substrate by functioning as property-bearers, they actually serve only as logical subjects. An implication of the interpretation I develop is that only space is extended by having parts outside parts; material bodies are spatially extended only in a derivative sense, via the presence of their constitutive qualities or powers in space

Causal Language and the Structure of Force in Newton’s System of the World

Although Newton carefully eschews questions about gravity’s causal basis in the published Principia, the original version of his masterwork’s third book contains some intriguing causal language. “These forces,” he writes, “arise from the universal nature of matter.” Such remarks seem to assert knowledge of gravity’s cause, even that matter is capable of robust and distant action. Some commentators defend that interpretation of the text—a text whose proper interpretation is important since Newton’s reasons for suppressing it strongly suggest that he continued to endorse its ideas. This article argues that the surface appearance of Newton’s causal language is deceptive. What does New- ton intend with his causal language if not a full causal hypothesis? His remarks actually indicate a way of considering the force mathematically, something he contrasts to the structure of the force as it really is in nature. In explaining that, he identifies a significant disjunction between the physical force itself and mathematical ways of considering it, and the text’s significance lies in its view of the force’s structure and in the questions raised about the relationship between mathematical representations and the physical world

Spiritual Presence and Dimensional Space beyond the Cosmos

This paper examines connections between concepts of space and extension on the one hand and immaterial spirits on the other, specifically the immanentist concept of spirits as present in rerum natura. Those holding an immanentist concept, such as Thomas Aquinas, typically understood spirits non-dimensionally as present by essence and power; and that concept was historically linked to holenmerism, the doctrine that the spirit is whole in every part. Yet as Aristotelian ideas about extension were challenged and an actual, infinite, dimensional space readmitted, a dimensionalist concept of spirit became possible—that asserted by the mature Henry More, as he repudiated holenmerism. Despite More’s intentions, his dimensionalist concept opens the door to materialism, for supposing that spirits have parts outside parts implies that those parts could in principle be mapped onto the parts of divisible bodies. The specter of materialism broadens our interest in More’s unconventional ideas, for the question of whether other early modern thinkers, including Isaac Newton, followed More becomes a question of whether they too unwittingly helped usher in materialism. This paper shows that More’s attack upon holenmerism fails. He illegitimately injects his dimensionalist concept of spirit into the doctrine, failing to recognize it as a consequence of the non-dimensionalist concept of spirit, which in itself secures indivisibility. The interpretive consequence for Newton is that there is no prima facie reason to suppose that the charitable interpretation takes him to deny holenmerism