Marleen Rozemond

ABSTRACTThe most prominent early modern argument against materialism is to be found in Descartes. Previously I had argued that this argument relies crucially on a robust conception of substance, according to which it has a single principal attribute of which all its other intrinsic qualities are modes. In the present paper I return to this claim. In Section 2, I address a question that is often raised about that conception of substance: its commitment to the idea that a substance has a single such principal attribute. Gonzalo Rodriguez-Pereyra and Daniel Garber have argued that this claim relies on Descartes's identification of substance with attribute. But I argue that it relies on his view that a substance has a single, unitary nature. In Section 3, I examine the role of this conception of substance in arguments found in Malebranche and Leibniz and compare these arguments with Descartes's.

The Clarke-Collins correspondence was widely read and frequently printed during the 18th century. Its central topic is the question whether matter can think, or be conscious. Samuel Clarke defends the immateriality of the subject of the mental against Anthony Collins’ materialism. This paper examines important assumptions about the nature of body that play a role in their debate. Clarke argued that consciousness requires an “individual being”, an entity with some sort of significant unity as its subject. They agree that body does not have this type of unity, because it consists of actually distinct parts.

Leibniz took pride in the Pre-established Harmony as an account of mind-body union. On the other hand, he sometimes claimed that he did not have a good account of such a union. I explain the tension by distinguishing between two importantly different issues that concern the union: body-soul interaction and the per se unity of the composite. Leibniz's positive evaluation concerns the issue of interaction rather than per se unity, R.M. Adams proposed that Leibniz did have the philosophical resources to account for a per se unity of the body-soul composite, in the form of Aristotelian scholastic solutions to that problem. I argue, by contrast, that Leibniz's notions of body and soul were too far removed from their scholastic predecessors for him to be able to deploy those resources in a compelling way.

Descartes's dualism, and his argument for it, are often understood in terms of the modal notion of separability. I argue that the central notions, substance and real distinction, should not be understood this way. Descartes's well-known argument for dualism relies implicitly on views he spells out in the Principles of Philosophy, where he explains that a substance has a nature that consists in a single attribute, and all its qualities are modes of that nature. The argument relies ultimately on a deeply rationalistic view of substance.

In this paper I explain several ways in which Descartes denied that the human soul or mind is composite and the role this idea played in his thought. The mind is whole in the whole and whole in the parts of the body because it has no parts. Unlike body, the mind is indivisible, and this is a different idea from the thought that mind and body are incorruptible. Descartes connects the immortality of the soul with its status as a substance and as incorruptible rather than with its indivisibility.

Descartes argued that the eternal truths, most prominently the truths of mathematics, are created by God. He was not explicit, however, about the ontological status of these truths. Interpreters have proposed interpretations ranging from Platonism and conceptualism. I argue for an intermediate interpretation: Descartes held they have objective being in God’s mind. In this regard his view was line with a prominent view in Aristotelian scholasticism. I defend this interpretation against objections based on divine simplicity and concerns about causation. I raise questions about the philosophical merit of these objections, but in addition I argue that there is good reason to think that Descartes himself did not think they were problems for the view. Seemingly conceptualist passages in the Principles, I argue, in fact address issues different from the ontological status of the eternal truths.