but will also reduce the amount of exercise people do (U->E) by an amount where the effect of the reduced exercise on weight exactly cancels out the direct weight reduction.
It’s unlikely that two effects will randomly cancel out unless the situation is the result of some optimizing process. This is the case in Milton Friedman’s thermostat but doesn’t appear to be the case in your example.
It wouldn’t be random. It would be an optimising process, tuned by evolution (another well known optimising process). If you have less food than needed to maintain your current weight, expend less energy (on activities other than trying to find more food). For most of our evolution, losing weight was a personal existential risk.
I had meant to suggest some sort of unintelligent feedback system. Not coincidence, but also not an intelligent optimisation, so still not an exact parallel to his thermostat.
It’s unlikely that two effects will randomly cancel out unless the situation is the result of some optimizing process. This is the case in Milton Friedman’s thermostat but doesn’t appear to be the case in your example.
It wouldn’t be random. It would be an optimising process, tuned by evolution (another well known optimising process). If you have less food than needed to maintain your current weight, expend less energy (on activities other than trying to find more food). For most of our evolution, losing weight was a personal existential risk.
I had meant to suggest some sort of unintelligent feedback system. Not coincidence, but also not an intelligent optimisation, so still not an exact parallel to his thermostat.
The thermostat was created by an intelligent human.
I never said the optimizing process had to be that intelligent, i.e., the blind-idiot-god counts.