Dr Kurt Harris made some insightful
comments about the food reward hypothesis (FRH) that made me reconsider my skepticism (though not necessarily abandon it, just yet). I thought the most interesting thing was concerning the mind/body problem:
One thing I like about FR is what Sean hates - the fact that it brings in the messy mind/body thing. This helps me explain many of the failures of LC that I see, as well as to tie in emotional eating - cases where even Paul Jaminet could customize your diet down to the molecule and you would still get fat because you are using food literally as a drug- you are not really hungry in the food sense so much as the "I want to stimulate myself with something" sense. These people definitely exist. I've seen many of them. You probably know some too if you think about it...
Apparently GT [Gary Taubes] hates it partly for that reason too. He insists that if you say fat is regulated by the brain, that means you are part of the energy balance paradigm, and not the "proper" fat cells and hormones one...and even more egregiously, I would guess he thinks that saying the brain is the locus instead of the more passive adipocyte is uncomfortably close to "gluttony and sloth".
I don't blame all obesity on gluttony and sloth, but the words do have meaning -
Is the mind/body problem really FRH's strength instead of a weakness? It's certainly an interesting question.
The mind/body problem has also been seen as the body/soul dichotomy (by non-secular philosophers) or the mind/brain dichotomy. It is tied up with artificial intelligence (AI) and goes to the root of some very basic questions like the existence and/or nature of
free will and self-awareness. I am going to start to approach this problem from the
strong AI vs what Martin Gardner calls the Mysterian's perspective, mostly citing Douglas Hofstadter's views as the strong AI advocate and Roger Penrose for the counter argument. I'm not crazy about the term Mysterian, but here's Martin Gardner talking about the opposing viewpoints in an 1991 interview:
You know the problem of consciousness is a hot topic right now. There have been half a dozen books published just in the last year or two. All of them are trying to figure out what it is in the brain that makes you self-aware. Of course, materialists like Moravec, and Churchland and his wife, are of the opinion that is it only going to be a short time until we figure out how the brain makes itself aware. But there is another school of philosophy that is coming into prominence now, with which I am sympathetic. They’re called the Mysterians. The Mysterians, and this includes a number of very top notch philosophers like Donald Chalmers, Colin Magin, John Searle, Thomas Nagel, Jerry Fodor, Noam Chomsky, and a bunch of others, are of the opinion, and I share this view, that consciousness is something so mysterious that no one has the slightest idea how the brain makes itself aware, and we may never find out. That’s the extreme Mysterian position, that we don’t have the intellectual capacity ever to solve the problem of consciousness. It may be something beyond our power to understand; the way calculus is beyond the mind of a chimpanzee. It’s an interesting point of view because it may be that there are some questions beyond the reach of science because of the limitations of our present brain. Perhaps in a million years from now, if we evolve with bigger brains, we’ll solve it. Roger Penrose is a Mysterian. This was one of the themes of his famous book The Emperor’s New Mind,
for which I wrote the introduction.
We Mysterians think consciousness won’t be understood for at least a long, long time. Also, the Mysterians believe that self-awareness and free will are two names for the same thing. If you try to imagine yourself without self-awareness, then you can’t imagine yourself having free will to make decisions. You’d be like an automaton.
The reason I don't like the Mysterian label is
that it can give the impression that there's something unknowable about
the human brain and hence free will and self-awareness. This is not
Penrose's position at all.
Roger Penrose hypothesizes that the brain exploits aspects of quantum
physics that are not yet understood. That, in order to understand how
the brain functions, one must also understand bizarre aspects of quantum
mechanics such as a photon seemingly being in two places at once in a
double-slit experiment. Penrose's views are, needless to say,
controversial. I happen to agree with Penrose, but this makes me an
outlier.
A core concept in the mind/body or mind/brain duality argument is that the mind could be exactly reproduced in some other medium like a computer or in a book or even in an ant colony. This is one of the running ideas in Hofstadter's
book,
Gödel, Escher, Bach: An Eternal Golden Braid:
Mind vs. Brain
In coming Chapters, where we discuss the brain, we shall examine whether the brain's top level-the mind-can be understood without understanding the lower levels on which it both depends and does not depend. Are there laws of thinking which are "sealed off" from the lower laws that govern the microscopic activity in the cells of the brain? Can mind be "skimmed" off of brain and transplanted into other systems? Or is it impossible to unravel thinking processes into neat and modular subsystems? Is the brain more like an atom, a renormalized electron, a nucleus, a neutron, or a quark? Is consciousness an epiphenomenon? To understand the mind, must one go all the way down to the level of nerve cells? [GEB, pp 315]
AI futurists (and sci-fi writers) who believe that humanity will one day (probably within a century) be able to upload itself into some sort of computer obviously think that the mind can be "skimmed" off the brain. A more gradualist approach is to consider that human brain could be emulated to a reasonable enough degree so as to create human-like intelligences once the signal processing properties of neurons are sorted out. This is Robin Hanson's approach. Robin writes
here:
My claim is that, in order to create economically-sufficient substitutes for human workers, we don’t need to understand how the brain works beyond having decent models of each cell type as a signal processor. Like the weather, protein folding is not designed to process signals and so does not have the decoupling feature I describe above. Brain cells are designed to process signals in the brain, and so should have a much simplified description in signal processing terms. We already have pretty good signal-processing models of some cell types; we just need to do the same for all the other cell types.
Hanson's ideas are not mutually exclusive with Penrose's. They could even be considered complimentary. Penrose thinks that a proper neuron/brain model requires a deeper understanding of physics than we currently have, Hanson thinks that the signal processing characteristics of neurons needs to to be correctly modeled.
But if neurons exploit quantum mechanics is it possible to build a model of a neuron without a deeper understanding of quantum mechanics, what Penrose calls,
correct quantum gravity (CGQ)?It doesn't seem possible.
For example, let's look at the famous "paradox" of
Schrödinger's Cat.
A cat is in a steel box, there is a vial of poison gas that is released via some sort of quantum process like a Geiger counter detecting the radioactive decay of some radioactive element such that there is a 50/50 chance of the poison being triggered within the course of an hour (note: no actual cats were harmed in this thought experiment).
Without looking in the box, there is no way to know the actual state of the cat according to our current understanding of quantum mechanics. There is a 50% chance that the cat is either alive or dead. This is the kind of thing Einstein was lamenting when he talked about God not playing dice with the Universe. Depending on one's interpretation, the Universe may split into one with a live kitty and one with a dead kitty, or the cat may exist in a state of superposition that is collapsed upon observation, or something else altogether. Or the state of the cat might simply be determined at any time by some as-yet-unkown CQG theory as Penrose conjectures.
The point being that in order to understand how a neuron employs quantum mechanics (assuming it actually does so) one would need to understand the paradox of Schrödinger's Cat, which would mean it would no longer be a paradox.
This is not to say that thinking machines can't be built without CQG. Steam engines were invented (apparently by the
Greeks) without a deep understanding of thermodynamics, Edison invented the phonograph without understanding acoustical wave mechanics and Fourier transforms, etc. So it is very possible that someone will invent a thinking, self-aware quantum computer intelligence before we come up with a
theory of everything that will explain how it works.
Wow, this has already gotten pretty long and I feel like I've just gotten started. I do plan to bring this around to food reward and addiction eventually, if only from a more philosophical perspective, I do think the question of how the brain works, and our lack of understanding thereof, is inextricably tied up with all of this.