The problem of mind-body interaction and the causal principle of Descartes’s Third Meditation

Abstract

The article analyses recent English publications in Cartesian studies that deal with two problems: (1) the problem of the intrinsic coherence of Descartes’s doctrine of the real distinction and interaction between mind and body and (2) the problem of the consistency of this doctrine with the causal principle formulated in the Third Meditation. The principle at issue is alternatively interpreted by different Cartesian scholars either as the Hierarchy Principle, that the cause should be at least as perfect as its effects, or the Containment Principle, that the cause should contain all there is in its effects. The author argues that Descartes’s claim (in his argument against the scholastic doctrine of substantial forms) that it is inconceivable how things of different natures can interact does not conflict with the acknowledgement of interaction between things of different natures in the case of soul and body. The case is made that Cartesian mind-body interaction can agree with both the Hierarchy Principle and the Containment Principle, because the Principle is about total and efficient cause, whereas in the interaction, mental and brain states are only partial (and plausibly, in the case of brains states, occasional) causes. In particular, in the case of the causality in the brain-to-mind direction, the mind is conditioned by brain states to form the corresponding specific ideas on the basis of its innate general ideas of movements, forms, colours, etc. Eventually, for Descartes, the most natural way to deal with worries about the possibility of mind-brain interaction is to rely on God’s omnipotence, which certainly enables Him to arrange for such interaction.