Online research in philosophy

In the Preface to the Principia (1687) Newton famously states that “geometry is founded on mechanical practice”. Several commentators have taken this and similar remarks as an indication that Newton was firmly situated in the constructivist tradition of geometry that was prevalent in the seventeenth century. By drawing on a selection of Newton’s unpublished texts, I hope to show the faults of such an interpretation. In these texts, Newton not only rejects the constructivism that took its birth in Descartes’ Géométrie (1637); he also presents the science of geometry as being more powerful than his Principia remarks may lead us to believe.

In the preface to the Principia (1687) Newton famously states that “geometry is founded on mechanical practice.” Several commentators have taken this and similar remarks as an indication that Newton was firmly situated in the constructivist tradition of geometry that was prevalent in the seventeenth century. By drawing on a selection of Newton's unpublished texts, I hope to show the faults of such an interpretation. In these texts, Newton not only rejects the constructivism that took its birth in Descartes's Géométrie (1637); he also presents the science of geometry as being more powerful than his Principia remarks may lead us to believe.

Newton's philosophical views are unique and uniquely difficult to categorise. In the course of a long career from the early 1670s until his death in 1727, he articulated profound responses to Cartesian natural philosophy and to the prevailing mechanical philosophy of his day. Newton as Philosopher presents Newton as an original and sophisticated contributor to natural philosophy, one who engaged with the principal ideas of his most important predecessor, Rene; Descartes, and of his most influential critic, G. W. Leibniz. Unlike Descartes and Leibniz, Newton was systematic and philosophical without presenting a philosophical system, but over the course of his life, he developed a novel picture of nature, our place within it, and its relation to the creator. This rich treatment of his philosophical ideas, the first in English for thirty years, will be of wide interest to historians of philosophy, science, and ideas.

This paper is the second of a two-part reexamination of causation in Descartes's physics. Some prominent contemporary scholars, including Gary Hatfield and Daniel Garber, have argued that Descartes is an Occasionalist about natural motion. On their reading, Descartes holds that God alone causes the motions that are not caused by the free actions of finite minds. Hatfield and Garber offer similar, but independent arguments that Descartes's views about physics – in particular, his arguments that the laws of nature are grounded in God's immutability – entail Occasionalism about natural motion. In this paper I argue contra Hatfield and Garber that Descartes's natural philosophy does not entail Occasionalism. Descartes holds that God is a direct efficient cause of every natural motion. Yet he does not take this to imply that bodies lack genuine causal powers. According to Descartes, God concurs with bodies to cause natural motion in such a way that both God and bodies are genuine, efficient causes of motion. I conclude by presenting an account of how Descartes's theory of body is compatible with the thesis that bodies have intrinsic active causal powers.

Descartes and the last Scholastics: objections and replies -- Descartes and the Scotists -- Ideas, before and after Descartes -- The Cartesian destiny of form and matter -- Descartes, Basso, and Toletus: three kinds of Corpuscularians -- Scholastics and the new astronomy on the substance of the heavens -- Descartes and the Jesuits of La Fleche: the Eucharist -- Condemnations of Cartesianism: the extension and unity of the universe -- Cartesians, Gassendists, and censorship -- The cogito in the seventeenth century.

In this paper I clarify what Newton could have meant when he insisted that gravity is a real force. I interpret Newton’s speculative treatment of gravity as a relational, accidental quality of matter that arises through what Newton calls “the shared action” of two bodies. I argue that when Newton drafted the first edition of the Principia in the mid 1680s, he thought that (at least a part of) the cause of gravity is the disposition inherent in any individual body, but that the force of gravity is the actualization of that disposition; a necessary condition for the actualization of the disposition is the actual obtaining of a relation between two bodies having the disposition. The cause of gravity is not essential to matter because God could have created matter without that disposition. Nevertheless, at least a part of the cause of gravity inheres in individual bodies and were there one body in the universe it would inhere in that body. On the other hand, the force of gravity is neither essential to matter nor inherent in matter, because (to repeat) it is the actualization of a shared disposition. A lone part-less particle would, thus, not generate a gravity field.

Cartesian method both organizes and impoverishes the domains to which Descartes applies it. It adjusts geometry so that it can be better integrated with algebra, and yet deflects a full-scale investigation of curves. It provides a comprehensive conceptual framework for physics, and yet interferes with the exploitation of its dynamical and temporal aspects. Most significantly, it bars a fuller unification of mathematics and physics, despite Descartes' claims to quantify nature. The work of his contemporaries Galileo and Torricelli, and of his successor Newton, illustrates conceptual possibilities Descartes left aside, due to his attachment to method.

: This article is concerned with Newton's appropriation of Descartes' ontology of true and immutable natures in developing his theory of infinitely extended space. It contends that unless the part played by the Platonic distinction between "being a nature" and "having a nature" in Newton's thinking is properly appreciated the foundation of his doctrine of space in relation to God will not be fully understood. It also contends that Newton's Platonism is consistent with his empiricism once the mediating role is made clear that the geometry of moving loci play in grounding his intuitions concerning infinite natures.

Machine generated contents note: Introduction Andrew Janiak and Eric Schliesser; Part I. Newton and his Contemporaries: 1. Newton's law-constitutive approach to bodies: a response to Descartes Katherine Brading; 2. Leibniz, Newton and force Daniel Garber; 3. Locke's qualified embrace of Newton's Principia Mary Domski; 4. What geometry postulates: Newton and Barrow on the relationship of mathematics to nature Katherine Dunlop; Part II. Philosophical Themes in Newton: 5. Cotes' queries: Newton's Empiricism and Conceptions of Matter Zvi Biener and Chris Smeenk; 6. Newton's Scientific Method and the Universal Law of Gravitation Ori Belkind; 7. Measurement and method: some remarks on Newton, Huygens and Euler on natural philosophy William Harper; 8. What did Newton mean by 'Absolute Motion'? Nick Huggett; 9. From velocities to fluxions Marco Panza; Part III. The Reception of Newton: 10. Newton, Locke, and Hume Graciela de Pierris; 11. Maupertuis on attraction as an inherent property of matter Lisa Downing; 12. The Newtonian refutation of Spinoza: Newton's Challenge and the Socratic Problem Eric Schliesser; 13. Dispositional explanations: Boyle's problem, Newton's solution, Hume's response Lynn Joy; 14. Newton and Kant on Absolute Space: from theology to transcendental philosophy Michael Friedman; 15. How Newton's Principia changed physics George Smith; Bibliography.