Soul-Body Interaction: Is the Problem Real?

The most frequently discussed aspect of the soul-body duality has been the interaction between the two. How can an immaterial something affect a material something else, and vice versa. This discussion tends to begin with Descartes (1596-1650), but the problem is that Descartes’ views on the matter are all too frequently over-simplified and, as usually stated, turn out to be cartoons of his thought. For example: bodies are of matter, and matter is the extended thing (res extensa); soul or mind is the thinking thing (res cogitans); it has no extension. But these two realms interact one with the other by means of the pineal gland. That’s the caricature.

The statements listed are, indeed, discoverable in Descartes’ extensive writings—but so is a great deal more. Descartes was a prodigious thinker, a diligent writer; whole tribes of modern theories can claim him as their father. He did not, for instance, insist that the soul has no extension; what he said was “that extension is not the principal attribute of the soul” (quoting an enlightening article in the Stanford Encyclopedia of Philosophy, titled “Descartes and the Pineal Gland,” found here). Indeed, the article just referenced makes it clear that Descartes wrote about every aspects of this subject. Those who wish to cite a famous authority can search René and find chapter and verse to justify their views.

The problem, it occurs to me, may stem from a faulty conceptualization of what we mean by soul. We insist on its immateriality—and when we use that term, it largely suggests a kind of emptiness; we have a tough time imagining the immaterial. The root of that conception is anchored in common experience; we don’t see souls (forget about ghosts for a moment). In part the rooting lies in Plato’s proof for the soul’s immortality; the argument is made in Phaedo; Plato there rests his case on incorruptibility and declares that all things made of parts are subject to change, hence to corruption. Therefore the soul, which is a unity and has no parts, is incorruptible and thus also immortal.

This whole nexus of ideas is tricky, slippery. Immateriality works nicely to prove immortality. But in Greek thought, not least in Plato’s, the soul is also a form. In Aristotle we have the concept of substance, a duality of matter and form. Form shapes matter; matter manifests form. But the interaction between these two is just as nebulous in general as that between the soul and the body is in the particular. Some kind of force is implied in the very concept of the union of matter with form.

Form must compel matter to shape itself either by attraction or by some kind of positively shaping impulse. If by attraction, we might imagine a kind of complex form of gravity. Indeed Descartes himself believed that the soul exerts a force of volition which is communicated to the body by means of the pineal gland. But if a force is present, able to move at least “animal spirits,” thus another but also subtle form of energy, the pure immateriality of the soul becomes problematical. What kind of force? Magic? To avoid magic, one is tempted to see the soul as somewhat more complex, and matter-like, as possessing capacities beyond a kind of point-like presence without extension.

Not that I have any problem with that. But if we admit a soul into the arena, a soul able to exert force—and to the extent that it does also has the ability passively to experience force—at that moment the supposedly insurmountable difficulty of interaction actually disappears. Never mind the pineal gland. You might say that it was a decent stand in for some kind of point or organ where the force of soul is transmitted to the body and where, at the same time, experience reaches the soul. The contact may be extremely subtle—in comparison, for example, with a sneeze—but it must have some kind of tangible reality, suggesting that the soul does have capacity, at some minimal level, to interact with what we normally call matter. It is this sort of meditation on the subject that encourages me to propose, as I have in earlier posts, that the soul may indeed interact with the material dimension at the subatomic level. And if you have a single fixed point of interaction then, as Archimedes said, he could lift the world—and humanity can move mountains or build dams.