Online research in philosophy

The rich connections between metaphysics and natural philosophy in the early modern period have been widely acknowledged and productively mined, thanks in no small part to the work of Margaret Wilson, whose book, Descartes, served as an inspirational example for a generation of scholars. The task of this paper is to investigate one particular such connection, namely, the relation between occasionalist metaphysics and strict mechanism. My focus will be on the work of Nicholas Malebranche, the most influential Cartesian philosopher after Descartes himself. I begin with two crucial facts about Malebranche’s philosophy: (1) Malebranche was an occasionalist, that is, he held that God was the only true cause, that all modifications of bodies and of minds can be produced by God alone. (2) Malebranche adhered firmly to strict mechanism. By strict mechanism, I mean the view, found most prominently in Descartes and in Boyle’s more ideological writings, that the qualities of bodies are exhausted by a very short list (size, shape, motion, and perhaps solidity) and that, most importantly, bodies interact only at contact by impact. Another way of describing this “contact action” requirement is as the thesis that the only fundamental laws of physics are laws of inertial motion and laws of the communication of motion at impact. In..

: Descartes provides an original and puzzling argument for the traditional theological doctrine that the world is continuously created by God. His key premise is that the parts of the duration of anything are "completely independent" of one another. I argue that Descartes derives this temporal independence thesis simply from the principle that causes are necessarily simultaneous with their effects. I argue further that it follows from Descartes's version of the continuous creation doctrine that God is the instantaneous and total cause of everything that happens, and that this is just what his physics demands. But although God is the total cause of everything, he is not the only cause, since Descartes considers it obvious that finite minds have the power to move bodies. In the face of this apparent paradox, several recent commentators have suggested that Descartes accepted the late scholastic view that God and finite causes somehow collaborate or concur in the production of numerically identical effects. But close examination reveals that the case for Cartesian concurrentism is weak. Fortunately, there is a simpler and more fruitful solution to the problem of reconciling divine and human action. I argue that that in Descartes's world certain motions, such as voluntary movements of our bodies, are causally overdetermined This account allows Descartes to avoid occasionalism without embracing an elaborate metaphysics of secondary causality. Finally, I argue that the overdeterminist interpretation sheds new light on two longstanding problems of Cartesian metaphysics. First, it resolves a serious difficulty with a standard reading of Descartes's conception of human freedom. Second, it offers a novel approach to the old problem of reconciling genuine human action with the principle of the conservation of total quantity of motion.

Descartes holds that God's will is immutable. It cannot be changed by God and, because He is supremely independent, it cannot be changed by anything else. Descartes' God acts by a single immutable will for all eternity, and there is no sense in which it is possible for Him to will or to have willed anything other than what He in fact wills. Passages in which Descartes might appear to be suggesting a different view are simply manifestations of his analytic method.

The core thesis of Malebranche’s doctrine of occasionalism is that God is the sole true cause, where a true cause is one that has the power to initiate change and for which the mind perceives a necessary connection between it and its effects. Malebranche gives two separate arguments for his core thesis, T, based on necessary connection and on divine power respectively. The standard view is that these two arguments are necessary to establish T. I argue for a reinterpretation of Malebranche’s strategy, according to which the Necessary Connection Argument alone is sufficient to establish T. The Divine Power Argument, which is anyway weaker, is needed not to support T but to bridge the gap between T and full-fledged occasionalism. Specifically, it is needed to rule out the existence of causal powers in nature, a scenario which is consistent with T but inconsistent with occasionalism.

: In this reassessment of Descartes' debt to his mentor Isaac Beeckman, I argue that they share the same basic conception of motion: the force of a body's motion—understood as the force of persisting in that motion, shorn of any connotations of internal cause—is conserved through God's direct action, is proportional to the speed and magnitude of the body, and is gained or lost only through collisions. I contend that this constitutes a fully coherent ontology of motion, original with Beeckman and consistent with his atomism, which, notwithstanding Descartes' own profoundly original contributions to the theory of motion, is basic to all Descartes' further work in natural philosophy.

: This paper interprets Descartes's use of the Scholastic doctrine of divine concurrence in light of contemporaneous sources, and argues against two prevailing occasionalist interpretations. On the first occasionalist reading God's concurrence or cooperation with natural causes is always mediate (i.e., concurrence reduces to God's continual recreation of substances). The second reading restricts God's immediate concurrence to his co-action with minds. This paper shows that Descartes's metaphysical commitments do not necessitate either form of occasionalism, and that he is more plausibly and charitably read as appropriating elements of Scholastic views on concurrence to bridge the gap between his metaphysics and physics.

Unlike many of Descartes’s other followers, Pierre-Sylvain Re´gis resists the temptations of occasionalism. By marrying the ontology of mechanism with the causal structure of concurrentism, Re´gis arrives at a novel view that both acknowledges God’s role in natural events and preserves the causal powers of bodies. I set out Re´gis’s position, focusing on his arguments against occasionalism and his responses to Malebranche’s ‘no necessary connection’ and divine concursus arguments.

Here I reexamine Duhem's question of the continuity between medieval dynamics and early modern conservation theories. I concentrate on the heavens. For Aristotle, the motions of the heavens are eternally constant (and thus mathematizable) because an eternally constant divine Reason is their mover. Duhem thought that impetus and conservation theories, by extending sublunar mechanics to the heavens, made a divine renewer of motion redundant. By contrast, I show how Descartes derives his law of conservation by extending Aristotelian celestial dynamics to the earth. Descartes argues that motion is intrinsically linear, not circular. But he agrees that motion is mathematically intelligible only where divine Reason moves bodies in a constant and eternal motion. Descartes strips bodies of active powers, leaving God as the only natural mover; thus both celestial and sublunar motions are constant, and uniformly mathematizable. The law of conservation of the total quantity of motion is an attempt to harmonize the constancy derived a priori with the phenomenal inconstancy of sublunar motions.

This paper is the first of a two-part reexamination of causation in Descartes's physics. Some scholars ? including Gary Hatfield and Daniel Garber ? take Descartes to be a `partial' Occasionalist, who thinks that God alone is the cause of all natural motion. Contra this interpretation, I agree with literature that links Descartes to the Thomistic theory of divine concurrence. This paper surveys this literature, and argues that it has failed to provide an interpretation of Descartes's view that both distinguishes his position from that of his later, Occasionalist followers and is consistent with his broader metaphysical commitments. I provide an analysis that tries to address these problems with earlier `Concurentist' readings of Descartes. On my analysis, Occasionalism entails that created substances do not have intrinsic active causal powers. As I read him, Descartes thinks that bodies have active causal powers that are partly grounded in their intrinsic natures. But I argue ? pace a recent account by Tad Schmaltz ? that Descartes also thinks that God immediately causes all motion in the created world. On the picture that emerges, Descartes's position is both continuous with, and a subtle departure from, the Thomisitic theory of divine concurrence.

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.