Lecture 14. October 7 and 13.
Afterthoughts. The second aspect of the Cartesian Paradigm to which I want to draw special attention is its substantial dualism, the claim that body and mind (or soul) are separate things: res extensa and res cogitans. Dualism as such, of course, is not new. The Bronze Age Greeks were dualists to a degree, Pythagoras, Plato, and the Neoplatonists were dualists. Aristotle was a dualist, but not a substantial dualist, because he did not say that soul was a thing.
What made Descartes’ dualism different from these earlier substantial dualism lies less in his conception of the soul, than in his conception of matter. The Scientific Revolution was developing a powerful, detailed, and new conception of the material world as a machine, and thus Descartes proposed that animal and human bodies are likewise machines. Human beings, then, must be seen as machines inhabited by souls that interact with them, raising the problems of interaction noted in the Lecture 12 post.
What emerge in the eighteenth century are alternatives to Cartesian dualism, along with alternatives to his conception of consciousness (Lecture 13 post). There are 3; in each, one aspect of Descartes’ own dualism is rejected as an illusion. The first to emerge is psychophysical parallelism, which we discussed in class in connection with Leibniz. Parallelism retains the separation of mind and body (it’s a dualism), but says that the apparent interaction between them is an illusion: Mind and body are synchronized, like 2 synchronized swimmers, but, like the swimmers, they are not causally connected.
The other two alternatives are monisms, which means that they say only one thing exists, the mind or the body, but not both. One form of monism is idealism, which we find in different forms in Berkeley and Kant. In ontological idealism, the material world does not exist — though there are many, many variations on idealism. They will not concern us much, because the more influential form of monism in psychology, especially American psychology, and in contemporary thought more broadly, is materialism. We have met materialism in Hobbes, La Mettrie, and in the French naturalists of the Enlightenment Project. Materialists hold (like the atomists) that only matter and space exist in reality, that there is no soul, and that therefore the mind (and the appearance of mind-body interaction) is some sort of an illusion.
Forethoughts. Together with the problems regarding the privacy of consciousness and the accuracy of introspection, Cartesian materialism helped push psychology towards behaviorism. Parallelism, which was quite popular among psychologists of the founding generation, says that while mind exists, it does not do anything. Materialism says that mind is an illusion. Thus to define psychology as the study of the mind — and remember, in the Cartesian version mind = consciousness — is to define it as the science of something pointless or as the science of nothing at all. As we will see, evolution adds a new aspect to the problem of mind and consciousness — is it adaptive? The Cartesian paradigm concerning mind and consciousness, already present as psychology’s working framework, is pre-set to answer, “No, it’s not.”