Brain Design and the Mind-Body Problem

Brain Design and the Mind-Body Problem

If you look at any organ of an animal body, you will find two things: a function for the organ and a design suited to that function. The organ’s design enables it to perform its function. That’s how nature works and it is hard to see how it could not work that way. For example, teeth have the function of chewing up food (inter alia) and they are designed to be sharp and hard—perfectly suited for their job in life. The heart has the function of circulating the blood and it is designed as a pump. The stomach functions to digest food and it has a design that enables it to do so (digestive juices etc.). We never find an organ that lacks a function, or has one but is not designed to carry it out. That would be a funny way for nature to work, especially the part of it known as evolution (it would be very un-Darwinian). In the case of the brain, we can say that the function of the brain is to think or experience or produce consciousness—to be the organ of mind. It has other functions too, relating to bodily regulation (homeostasis etc.), but chief among its functions is its role in generating and controlling the mind. To be brief, I will say that the function of the brain (part of it anyway) is to think—where thinking has further functions in the animal’s life. This is what the brain is for—why it evolved in its present form to begin with. And clearly it performs this function, adequately or excellently; it is good at controlling and producing the mind. It is expert at the management of pain sensations, for example; it is not incompetent or badly put together for that purpose. Why? Because it was designed to do the job in question (by natural selection, as we now know). If we knew that the brain had been designed with that purpose in mind by an intelligent designer, we wouldn’t doubt the excellence of its design—at least as good as the design of the eye. Examining it, we would expect to find evidence of its design excellence—suitable parts, processes, engineering principles. We would expect to find a functioning mind machine (it might not be “physical”).[1] We would examine it and say, “Yes, exquisitely designed for its purpose—just look at the way the machine carries out its appointed task”. It would be like looking under the hood of a Rolls-Royce or inside a cell phone. We would not expect to find something structureless, amorphous, unsuited for its apparent function. We would expect a design-function fitsuch that you could infer the one from the other, or at least not to be surprised at the apparent lack of fit.

But that is exactly what we do not find: form and function seem miles apart. It’s a bit like opening up the head to find only a bucket of sand—what has this got to do with that? How do the biological cells we call neurons form a design that enables the brain to serve as the organ of consciousness? What has the anatomy of the neurons got to do with thought and feeling? They are much like other cells of the body, and they form a network that does not portend what they are supposedly designed to do. For a mind-machine, they seem spectacularly poorly designed—there is not a chance in hell that they could generate mind as we know it. So it appears anyway. Yet they must have a workable design, since the brain does in fact perform the function in question. This, ladies and gentlemen, is the mind-body problem: the problem of finding an intelligible relation between the mind and the body (brain). We might call it the “brain design problem” or just the “design problem”. And the problem is that we have absolutely no idea what the design might be—how the brain might be constructed so as to perform its function. What we see before us gives us no clue as to what this design might be, and indeed seems to preclude the brain from instantiating such a design. Let’s consider what kind of design might occur to us independently of knowing the actual contents of the head. First, we would suppose that a machine for a mind would have to be composed of similar things to the mind—things like thoughts and sensations. If you want to construct an entity that thinks, you had better start with thought-like components—not with chemicals (they don’t generally issue in thinking devices). So, the “brain” needs to consist of mind-like elements—but it doesn’t. What about mental processes? Processes like inference seem remote from brain processes: electro-chemical propagation along a neve fiber is nothing like logical inference—a conscious rational process. Belief formation is nothing like a pattern of neural excitation. The gap between the electro-chemical brain and the rational mind is enormous, so we can’t find the design of the latter in in the former. Nor will the idea of immateriality help: it’s hard to think of any design that could enable a machine, material or immaterial, to think and feel. Is the brain, then, not a machine, like the heart or the teeth or the kidneys, but something else entirely—which still has a design? But what could have a design and not be a machine in the intended sense? That is, what could have a structure and composition suited to achieve a certain end and yet have no design to that end? The brain must have a design that suits it to managing the mind, but that design is invisible and scarcely imaginable. On the face of it the brain is not designed to engender the mind—and yet it does. That is the mind-body problem—the invisible design problem.

We should note that none of the standard positions on the mind-body problem even addresses the problem as so-conceived. Dualism says nothing about the design of the immaterial substance supposedly at the root of the mind, and a fortiori about the brain as correlated with the mind. Materialism simply proposes an identity or reduction without enquiring into design features of the material brain: it says that pain is C-fiber firing, but it doesn’t tell us how C-fiber is designed so as to enable it to function as pain, phenomenologically speaking? You could be a sand materialist holding that mental phenomena are identical to collocations of sand—but what is it about sand that suits it to function mentally? This point applies to both token and type identity theories–they are simply silent on the design question. Functionalism might claim at least to address the question by suggesting that mental states are holistic causal roles and brains are designed to manifest such causal roles (interconnected neurons arranged in net-like structures—“neural nets”). But the causal roles being invoked here are as different as chalk and cheese, and anyway the mind is not reducible to causal roles. The classical answers to the mind-body problem are simply sidestepping the really difficult problem, namely what kind of design the brain has that enables it to discharge its allotted function. As far as I can see, only the brain presents such a problem—no other organ in nature is similarly inscrutable. Even DNA has a design that makes its functions intelligible (embryogenesis, heredity). The brain is unique in having a function that defies explanation in terms of its design. Whether made by evolution or intelligent design, we draw a blank trying to elucidate its design features qua mind-machine. Please don’t say that computers are designed to have minds in virtue of their informational-computational properties: such properties are a far cry from the conscious mind as we know it, as has often been pointed out. The plain fact is that don’t know the mind-making design of the brain, and may never know.

Is there any way out of the mysterious-design predicament? Yes, if you have prodigious bullet-biting proclivities: you could say that the mind does not have any properties that fail to be designed for in the brain as currently conceived. The brain has an electro-chemical design, suiting it to bodily regulation and the like, and there is really no more to the mind than that—anything else is illusion, myth, fantasy. That is, you could go eliminative. No thanks, I say. Or you might try to pump up the brain with unusual fancy properties—as with panpsychism. You might try saying that the brain incorporates postulated micro-mental properties that are built into a design plan that can in principle produce the mind as we know it. This would require a type of design that has hitherto been unspecified, and of course it presupposes panpsychist metaphysics. The point I am making is that any such hypothesis must face the design question: how do you design a machine (an organ) that can exploit micro-mental properties in a device that performs mental functions? This is a condition of adequacy on purported solutions to the mind-body problem: it must fill the design gap. It can’t just be ontological (monism, dualism, etc.); it must be design-specific. You can’t solve the blood circulation problem by simply declaring that the organ responsible is the heart (that organ); you have to say that the heart circulates the blood by being a pump. Similarly, you can’t solve the mind-body problem by declaring that the mind simply is the brain; you have to say what it is about the brain that enables it to generate a mind—it does so by being a what? Here is where things get difficult, vertiginous, truly mysterious. For nothing comes to mind: not an extended substance, not a biological entity, not an electro-chemical factory, not an information-processing plant, not a home for stray particles of mentality, not a steam room of peculiar vapors. The brain doesn’t have the design of anything we know or can conceive; it must therefore have a very special kind of design that is hidden from us. This fact in itself is hard to get one’s mind around. How could the brain be so special? This is the hard heart of the mind-body problem—what gives the brain this remarkable power.[2]

[1] The OED defines “machine” as “a structure of any kind, material or immaterial; something constructed”, and also “the human or animal frame”; there is no commitment to a mechanical-physical conception of machine. The same goes for the word “machinery”: it too has a very elastic use. So, there is nothing question-begging about describing the brain as a machine for managing the mind. The intuitive idea is that of a system of coordinated elements that functions effectively to give rise to the mind and its operations—the skeleton (“frame”) of the mind, as it were. Its nuts and bolts, its basic plan, its deep architecture.

[2] When I talked about property P in “Can We Solve the Mind-Body Problem?” I tacitly assumed that P is a design property—it is designed to do a certain job. Being a pump is the property P for the heart, but we have nothing analogous for the brain and consciousness. Yet it must be there on pain of postulating miracles. Nature works by containing designs—of molecules, cells, organs, bodies, minds. We need a design metaphysics.