Gary Taubes’ Good Calories, Bad Calories is overall a very good book, especially in its description of evidence. But there is also this:
Life is dependent on homeostatic systems that exhibit the same relative constancy as body weight, and none of them require a set point.
How does he think body temperature is regulated? Taubes continues:
It is always possible to create a system that exhibits set-point-like behavior or a settling point without actually having a set-point mechanism involved. The classic example is the water level in a lake, which might, to the naive, appear to be regulated from day to day or year to year, but is just the end result of a balance between the flow of water into the lake and the flow out.
No, lakes do not “appear to be regulated” because they do not exhibit anything like hunger or feeling cold. When the water level in a lake is lower than usual, nothing happens to push the level back up. Taubes continues:
When Claude Bernard discussed the stability of the milieu interne and Walter Cannon the notion of homeostasis, it is was this kind of dynamic regulation they had in mind, not a central thermostatlike regulator in the brain that would do the job rather than the body itself.
Michel Cabanac would not enjoy reading this. Whatever Bernard and Cannon had in mind, there is a “central thermostatlike regulator in the brain” that controls body temperature. It makes us seek warmth — take a warm shower, drink hot drinks, put on a jacket — when our body temperature is too low and do the opposite — such as drink cold drinks and eat ice cream — when our body temperature is too high. When our body temperature is too high, we find a warm shower more pleasant than when our body temperature is too low. These changes are obvious — at least, once you look for them — and imply a thermostat in the brain.
I don’t know if you’ve seen this:
https://www.arthurdevany.com/webstuff/WhyWeGetFat.pdf
Thought you might be interested in it, given your writings about set points and evolutionary explanations.
I don’t know much about blood sugar regulation. But it is clear that with body weight and body temperature, counter-acting behavior (e.g., seeking warmth when you are cold) helps keep the level constant. This implies brain involvement and a regulatory system more complicated than the forces controlling the level of a lake.
I find it hard to know how much of this is semantic. Science often proceeds by understanding biological functioning in terms of technology. We didn’t know the heart was a pump until someone invented a pump; that is not metaphoric — the heart actually is a pump of sorts. I’m told that radar technology helped get the mind back into psychology in the 1940s…
Understanding weight control in terms of a thermostat may just be a metaphorical mapping where some parts hold but others do not. There is a regulatory system with causal interactions that can be identified — exposure to poorly learned tastes reduces hunger, to strongly learned ones increases it; enduring hunger and losing weight (in my view) increases “sensitivity” or readiness for the system to learn or respond to taste-calorie associations — but how much does it really matter if we add the notion of an entity, a noun, “a thermostat in the brain”. If we find some controlling mechanism in the brain that does that, fine. And is there really a “point” that the “brain” sets in some way? Is this a metaphor? Or is there just a set of causally interactive processes at work that are easier to understand if we talk this way? When do we need to say that there is a central regulator regulating a biological system and when do we say there is just a system that regulates itself? Does positing a “thermostat in the brain” explain the system or merely re-describe it? Perhaps that will only be known if one is identified. Or is it obvious that there *must* be one given the functioning of other neurobiological systems?
How do we empirically determine the difference between a system that merely behaves as if there were a thermostat in the brain and a system where there actually is one? Ad nauseum…
Why does it matter whether there is a “thermostat in the brain”? That Taubes is wrong about something pretty obvious makes it more plausible to me that he wrong about something less obvious — whether there is a set point for weight.
If you think there is a set point for weight you can entertain the possibility that the set point is adjustable. If you think it is adjustable you can entertain the possibility that it is adjusted based on environmental conditions (as Cabanac concluded the temperature set point is). If you believe in an adjustable set point based on environmental conditions you can begin to wonder what the exact rule is. The more detailed your theory, the easier it is to derive predictions that you can test.
Still not convinced there is a disagreement of substance. Taubes is not denying that you can intervene in homoestatic systems; you can reduce body temperature with aspirin or cold. Or even change the depth of a lake. He is just saying the regulatory system may be the whole body itself rather then a thermostatic system in the brain, a little homunculus in charge of things. The existence of the system for hunger control is to me, undeniable; and god knows we can intervene in it, but whether there is the equivalent of a thermostat in the brain may be an open question. The causal system may resemble a thermostatic system without their being some special mechanism “in the brain” that “sets” hunger levels.
Yes, thinking of it in the way you do may lead heuristically to better interventions. It actually seems kind of conceptually tricky because we have a biochemical neurological system interacting with consciousness — awareness of flavors and memory of previous flavors — so straight biochemical concepts are not quite enough. The thermostat has no consciousness; it’s straight chemistry. The brain/body does…
John Searle claims there is a lot of intellectual confusion because people confuse behaving according to a rule, and following a rule…
Assuming all of this makes it easier to intervene. You are making a conceptualist argument; there is a system that can be intervened upon sure, I guess the question is whether it “sets” a hunger level the way a thermostat does, or whether what is set, is constantly changing, which is where the metaphor breaks down… Of course thinking about it this way enables you to intervene; it clearly is a system of causal forces, analogous to a thermostat…
Part of the system can be destroyed and it no longer regulates; a person can have a stroke and their temperature regulation system can fail… Whether there is a homunculus in the brain, or just a more diffuse systemic bodily system. Taubes would not deny that you can intervene in the other systems; you can lower body temperature with aspirin or cold packs; you can lower hunger by getting calories without taste, or sugar water (the latter would blow Taubes’ mind).