As a Stoic, am I committed to some kind of fundamental mind-body dualism? And if so, how on earth can I reconcile that with my understanding, as a scientist, that dualism has become untenable at the least since the second part of the early 20th century, particularly with the publication of Jacques Loeb “The Mechanistic Conception of Life”? (Not to mention earlier sharp criticism by Thomas Henry Huxley, the famous “Darwin’s bulldog.”)

Let me be crystal clear here, vitalism is dead in biology, buried by the same arguments deployed by Loeb a century ago (and a complete dearth of empirical evidence in its favor). As he put it: “It is, therefore, unwarranted to continue the statement that in addition to the acceleration of oxidations the beginning of individual life is determined by the entrance of a metaphysical ‘life principle’ into the egg; and that death is determined, aside from the cessation of oxidations, by the departure of this ‘principle’ from the body. In the case of the evaporation of water we are satisfied with the explanation given by the kinetic theory of gases and do not demand that, to repeat a well-known jest of Huxley, the disappearance of the ‘aquosity’ be also taken into consideration.”

Vitalism is not likely to come back. Indeed, nowadays it is a pseudo-metaphysical position that in turn is invoked in one form or another to support pseudo-scientific notions, such as therapeutic touch, chiropractic (the so-called the Palmers’ Innate), spiritual healing, acupuncture, and a host of others.

Why should a Stoic care? Because at the least superficially, Stoic metaphysics is dualistic. The Stoics believed that there are two organizing principles in the universe: passive matter and active intelligence, which is how they distinguished biological organisms from inanimate objects, and moreover human beings from other animals. Inanimate objects are infused only with the passive principle, while living organisms also carry the active one, and human beings have enough of it to actually acquire the ability to reason.

The Stoics referred to the two principles as theos (=God, Nature, fate, causality, reason) and hylê, which just meant matter. According to Anthony Long, in his essay “Stoicism and the philosophical tradition: Spinoza, Lipsius, Butler” (on which I have already commented), the Stoics reserved the word “substance” for the passive principle and used the word “cause” for the active one.

This seems pretty straightforwardly dualistic, doesn’t it? And therefore, based on what I wrote above, not at all in line with modern science. What is a modern Stoic to do? There are three, not mutually incompatible, ways out of this:

i) Long’s further explanation of what the Stoics, exactly, thought.

ii) Lawrence Becker’s modern interpretation of the Stoic dictum to “follow nature.”

iii) My proposal for a pragmatic dualism.

Beginning with Long, then, after his initial explanation of the standard Stoic “dualistic” view he qualifies: “the Stoic principles, notwithstanding their duality, are completely inseparable and correlative; hence, the world that they constitute is unitary rather than dualistic. Its unity is evident in the Stoic claim that, sub specie aeternitatis, the world (kosmos) is ‘God himself, who is the individual quality consisting of all substance’ (DL VII 137).” (DL refers to Diogenes Laertius, Lives of the Eminent Philosophers) Moreover: “the Stoics’ God [again = Nature, fate, causality, reason] is an extended thing; there is no part of matter in which he is not physically present.” Which means that the Stoics were not really vitalists after all, since the élan vital is assumed to enter and exit bodies (which causes life and death).

In fact, it looks like the Stoics thought in terms of quantities, not qualities. Again from Diogenes Laertius: “The divine mind or thought pervades every part of the world, just like the soul in us. But it pervades some parts to a greater extent and others to a lesser degree. Through some parts it passes as ‘coherence,’ as through our bones and sinews, and through other parts as ‘intellect,’ as through our mind” (DL VII 138– 9).

Seen in this light, then, Stoic metaphysics is only superficially dualistic, and its purpose was to provide a kind of quantitative account for the differences among inanimate objects, vegetative organisms, animals, and humans. That is why Stoicism is, in my mind, better interpreted as pantheistic than panentheistic. (As an aside note, Long remarks that one of the comparatively few differences between the Stoics and Spinoza is that the latter, but not the former, saw God as infinite in extension. Spinoza, then, was a panentheist, contra the linked Wiki entry.)

Becker’s take on the issue, I suspect, would be different. In chapter 5 of his A New Stoicism, he re-interprets the famous Stoic dictum, “follow nature,” as “follow the facts”: “Following nature means following the facts. It means getting the facts about the physical and social world we inhabit, and the facts about our situation in it — our own powers, relationships, limitations, possibilities, motives, intentions, and endeavors — before we deliberate about normative matters.”

There is plenty of textual evidence to support Becker’s interpretation, which he goes into in detail in the commentary to the same chapter. The idea, then, would be that even if the ancient Stoics actually adopted a dualist view of the cosmos and of human nature, they would have adjusted their metaphysics to keep them in synch with the findings of science. Seneca expressly said that doctrines need to be constantly revised because human nature keeps progressing: “Let us be satisfied with what we have discovered, and leave a little truth for our descendants to find out” (Seneca, Natural Questions VII.16).

Finally, my proposal, what I call pragmatic dualism. Here is what I mean. Whenever we say something like “I’ll need all my physical and mental strength to deal with this,” we don’t need to posit that our body and our minds are, in fact, distinct entities or substances. I’m sure some, maybe even many, people really do subscribe to this sort of “folk theory,” as philosophers refer to them, of the mind. But I certainly don’t. I know perfectly well that my mind is not an object, but rather the activities resulting from the interactions among my brain (which is a physical part of my body), the rest of my body, and the outside world — both in terms of physical circumstances and socio-cultural ones. Indeed, I prefer to refer to “minding,” a verb, rather than to the “mind,” implying an object. Minding is what the brain does when it processes internal and external stimuli, like breathing is what the lungs do under the proper physiological conditions.

Nonetheless, it makes perfect sense for me to “separate” my mind from my body for practical reasons. If I have a problem with the first I go to the psychologist, while for the second I visit my general practitioner and whatever specialist she recommends (then there is psychiatry, somewhere in between). In other words, psychological descriptions of human reality are perfectly valid and useful, without having to somehow imply a different ontology of mental objects and processes from physical ones.

This is also how I make sense of mind-body interactions: I recently got food poisoning and was sick for a night. The following day my “mind” wasn’t right either. It’s not like my brain processed the toxin, it’s that when one is tired and physically weak one has a hard time concentrating on stuff, like writing blog posts. It works the other way around as well: as I’m writing this I found out that my electronic payment to the tax office didn’t go through because of a mistake, and taxes are due tomorrow! Even though I know I can deal with the problem, I’m having trouble focusing on my work (which might explain the quality of this essay), and I feel vaguely sick to my stomach. My digestive system doesn’t really have anything to do with money and electronic bank transfers, and yet.

What I’m getting at is that talking “as if” our minds and bodies were two different things interacting with each other, rather than the manifestation of a uniform underlying reality, as they are according to modern science, is not only permissible, but very useful, and indeed pretty much impossible to avoid. Just try doing away with psychological vocabulary, to do what “eliminativists” in philosophy of mind, like Paul and Patricia Churchland, have been counseling us to do for decades: instead of “I feel pain,” get used to say “my C-fibers fired,” and do that for every mental process or psychological state. You end up looking really silly really soon.

So, modern Stoics reading Marcus Aurelius and his repeated counsel of ignoring the problems of the body and exercise instead our “ruling faculty” have at the least three options to deal with the charge of unscientific dualism. Personally, I’ll take all three.