Although not all of the various proponents of materialism (proponents of behaviorism, physicalism, the identity theory, functionalism, and strong AI) will admit this openly, they all deny that consciousness exists as a separate phenomenon. I think the mind / body problem is a crucial one and that any philosopher should have a position on it that he is willing to defend. Popper’s essay, “Language and the Body-Mind Problem,” attacks the “two language solution” and the behaviorist solution to the mind / body problem. Along the way he presents a cogent little argument against the “machine argument” which in modern dress is used by strong AI proponents like Daniel Dennett. Popper’s refutation follows very much along the lines of John Searle’s arguments against this position: a thermometer or even a very, very sophisticated robot, can express, but cannot intend. Searle calls this the difference between syntax and semantics. Computers can follow rules, but they can’t mean what they say. And I don’t wish to argue with this.
Popper’s positive position on this issue is central to his theory of knowledge. This is the famous “three worlds or universes” picture. Popper says in “Epistemology Without a Knowing Subject” that this position is presented “without taking the words ‘world’ or ‘universe’ too seriously.” I agree that one shouldn’t take these seriously. My thinking on this is still in progress, but I find the distinctions between “monism,” “dualism,” and “pluralism” get more slippery the more one investigates them. What interests me here is Popper’s positive position on the mind / body problem as he presents it in his joint book with John C. Eccles, The Self and It’s Brain. The position here is not substance dualism.
Searle, in his book Mind, misrepresents Popper’s (if not Eccles’) position as “substance dualism.” “Actually they go Descartes one better and also postulate World 3, a world of “culture in all its manifestations.” Searle clearly finds this position preposterous. He says “It is important to understand what an extreme doctrine substance dualism is. According to substance dualism our brains and bodies are not really conscious. You body is just an unconscious machine like your car or your television set. Your body is alive in the way that plants are alive, but there is no consciousness to your body. Rather, your conscious soul is somehow attached to your body and remains attached to it until your body dies, at which time your soul departs. You are identical with your soul and only incidentally inhabit this body.” Searle makes this sound like a ridiculous position, and I agree that it is, but this is not the position that Popper takes in his portion of The Self and It’s Brain.
I would call Popper’s position “process pluralism” in that he insists that neither the mind nor the body part of the mind / body problem is a substance at all. Popper says “Thus one may say that the results of modern physics suggest that we should give up the idea of a substance or essence. They suggest that there is no self-identical entity persisting during all changes in time (even though bits of matter do so under “ordinary” circumstances); that there is no essence which is the persisting carrier or possessor of the properties or qualities of a thing. The universe now appears to be not a collection of things, but an interacting set of events or processes (as stressed especially by A.N. Whitehead).” Likewise the mind part is not a substance either: clearly mental activity and cultural knowledge, Popper’s other two “worlds” are not substances or places. They are, as Popper insisted beginning with the Logic of Scientific Discovery, on-going processes, hopefully leading to verisimilitude (or not.)
I find this position a credible stand on the mind / body problem. I think it is interesting to compare it to the position from a totally different philosophical tradition, Buddhism. This is clearly a long story, which I cannot tell here, but I will just say that I would like to compare Popper’s “process pluralism” with the central tenet of Buddhism, the doctrine of dependent origination. This is the “middle way” which Reverend Gotama (also known as the Buddha) took between the Scylla of “eternalism” and the Charybdis of “materialism.” We are conditioned by the previous events in our life histories, but at each moment we are free to act. Gotama presented several versions of dependent origination in the Pali Canon, but the ten-step version presented in the Mahanidana Sutta (Digha Nikaya, 15) is the simplest: ageing and dying is conditioned by birth, birth by existence (bhava), existence by attachment (upadana), attachment by desire (trsna), desire by experience (vedana), experience by contact or stimulus (sparsa), contact by sentient body (namarupa), which is conditioned by consciousness (vijnana), and which in turn is conditioned by sentient body (namarupa again). Emphasis should be placed on the last three: there is an interaction between consciousness and the sentient body. This seems similar to the interactionism upon which Popper insisted.
I have always liked J.L. Austin’s phrase that dichotomies like annihilationism and eternalism, materialism and idealism, and sense data versus material things, “live by taking in each other’s washing – what is spurious is not one term of the pair, but the antithesis itself.” Reverend Gotama spurned the two extremes of “the soul theory” and “the brain theory”. Popper seemed to want to grasp both horns of the dilemma. This might be likened to the “dialetheism” of Graham Priest. My current position is that I like Reverend Gotama’s middle way, Parmenides be damned.