A real wealth of papers at the OpenMind site, presided over by Thomas Metzinger, including new stuff from Dan Dennett, Ned Block, Paul Churchland, Alva Noë, Andy Clark and many others. Call me perverse, but the one that attracted my attention first is the paper The Neural Organ Explains the Mind by Jakob Hohwy. This expounds the free energy theory put forward by Karl Friston.
The hypothesis here is that we should view the brain as an organ of the body in the same way as we regard the heart or the liver. Those other organs have a distinctive function – in the case of the heart, it pumps blood – and what we need to do is recognise what the brain does. The suggestion is that it minimises free energy; that honestly doesn’t mean much to me, but apparently another way of putting it is to say that the brain’s function is to keep the organism within a limited set of states. If the organism is a fish, the brain aims to keep it in the right kind of water, keeps it fed and with adequate oxygen, and so on.
It’s always good to get back to some commonsensical. pragmatic view, and the paper shows that this is a fertile and flexible hypothesis, which yields explanations for various kinds of behaviour. There seem to me to be three prima facie objections. First, this isn’t really a function akin to the heart pumping blood; at best it’s a high level meta-function. The heart does blood pumping, the lungs do respiration, the gut does digestion; and the brain apparently keeps the organism in conditions where blood can go on being pumped, there is still breathable air available, food to be digested, and so on. In fact it oversees every other function and in completely novel circumstances it suddenly acquires new functions: if we go hang-gliding, the brain learns to keep us flying straight and level, not something it ever had to do in the earlier history of the human race. Now of course, if we confront the gut with a substance it never experienced before, it will probably deal with it one way or another; but it will only deploy the chemical functions it always had; it won’t learn new ones. There’s a protean quality about the brain that eludes simple comparisons with other organs.
A second problem is that the hypothesis suggests the brain is all about keeping the organism in states where it is comfortable, whereas the human brain at least seems to be able to take into account future contingencies and make long-term plans which enable us to abandon the ideal environment of our beds each morning and go out into the cold and rain. There is a theoretical answer to this problem which seems to involve us being able to perceive things across space and time; probably right, but that seems like a whole new function rather then something that drops out naturally from minimising free energy; I may not have understood this bit correctly. It seems that when we move our hand, it may happen because we have, in contradiction of the evidence, adopted the belief that our hand is already moving; this belief serves to minimise free energy and our belief that the hand is moving causes the actual movement we believe in.
Third and worse, the brain often seems to impel us to do things that are risky, uncomfortable, and damaging, and not necessarily in pursuit of keeping our states in line with comfort, even in the long term. Why do we go hang-gliding, why do we take drugs, climb mountains, enter a monastery or convent? I know there are plenty of answers in terms of self-interest, but it’s much less clear to me that there are answers in terms of minimising free energy.
That’s all very negative, but actually the whole idea overall strikes me as at least a novel and interesting perspective. Hohwy draws some parallels with the theory of evolution; like Darwin’s idea, this is a very general theory with alarmingly large claims, and critics may well say that it’s either over-ambitious or that in the end it explains too much too easily; that it is, ultimately, unfalsifiable.
I wouldn’t go that far; it seems to me that there are a lot of potential issues, but that the theory is very adaptable and productive in potentially useful ways. It might well be a valuable perspective. I’m less sure that it answers the questions we’re really bothered about. Take the analogy of the gut (as the theory encourages us to do). What is the gut’s function? Actually, we could define it several ways (it deals with food, it makes poop, it helps store energy). One might be that the gut keeps the bloodstream in good condition so far as nutrients are concerned, just as the lungs keep it in good condition in respect of oxygenation. But the gut also, as part of that, does digestion, a complex and fascinating subject which is well worth study in itself. Now it might be that the brain does indeed minimise free energy, and that might be a legitimate field of study; but perhaps in doing so it also supports consciousness, a separate issue which like digestion is well worthy of study in itself.
We might not be looking at final answers, then – to be fair, we’ve only scratched the surface of what seems to be a remarkably fecund hypothesis – but even if we’re not, a strange new idea has got to be welcome.