Thinking About Health

Dr. Michael Eades has a very interesting recent post entitled “More braying from Bray.” It will teach you what you need to know to make yourself healthier, but it is also a good read in reasoning and doing science. Dr. Eades says such things as:

After giving short shrift to [Gary Taubes’] hypothesis of obesity, Dr. Bray then goes on to lay out in great detail his own theory of obesity as represented by the Rube Goldbergesque diagram at the top of this post.  Bray’s entire hypothesis, for which he recruits leptin, insulin, the brain, glucocorticoids, and God knows what else to help make his point, is based on a faulty premise.  But it’s a faulty premise that he has accepted uncritically. His hypothetical model of obesity, he authoritatively states

starts with the First Law of Thermodynamics, which states that the change of energy in a closed system is the difference between the heat added to the system and the work done by the system.

Dr. Bray then restates this hypothesis (and the First Law) in the form of this equation:

Δ E = Heat (q) – Work (w)

Readers of this blog know this as the energy balance equation, which looks like this in its more familiar form: Δ Weight (the Δ means change) = Energy in (food) – Energy out (exercise plus metabolism)

The fatal flaw in Dr. Bray’s hypothesis (which is a flaw we’ve discussed often in these pages) is that he doesn’t understand that the components on the right side of the equal sign are not independent variables.  They are dependent variables.  If one eats less, the rate of metabolism falls to compensate.  If one exercises more, the appetite increases, and one eats more to compensate. Were these components truly independent variables, life would be easier (but we may not have survived).  According to Dr. Bray, Anthony Colpo, and countless others, however, these components are independent variables.  Eat less, say they, and you’ll lose weight.  Which is true, to a point.  But once the energy-out component of the equation kicks in, weight loss stalls, even if you are eating less, a fact everyone who has ever dieted knows.  Exercise more, they pontificate, and you’ll lose weight.  Which, again, works (maybe) in the very short term.  But once appetite kicks in, you unconsciously eat enough more to compensate for your increase in exercise, as anyone knows who has tried to lose weight by walking or other exercise alone without consciously restraining eating.

Fascinating. Read it all. But Dr. Eades’ positive evaluation of Karl Popper is wrong. Popper was wrong on induction and wrong on reason. His theory of mind came from the German philosopher Immanuel Kant — as did the theory of mind of John Dewey, the destroyer of modern American education. Immanuel Kant said, in essence, that we could not ever know “real reality.” We were cut off from the world in virtue of having a consciousness and a mind. No, he didn’t say we were subject to error. Yeah, we can be wrong or can lie. Kant said we could not, in principle and by our nature, know the real world. Popper follows suit by saying that induction can never be certain. (Umm…and on what basis does he claim to know that? By studying the facts…i.e., by generalizing, i.e., by induction? So he’s certain, by induction, that induction does not work?) Popper claimed and unleashed on unsuspecting mankind the idea that we can never know any induction for certain, that all we could do was guess and wait to see if our guess was wrong. His idea of mankind is like a blind man who guesses to walk a certain way, then walks until he bumps into a wall or gets run over by a car or falls into a hole. Induction gives us certainty. But like any process of reasoning, you have to know how to use it — you have to know its laws and methods (which the human race is still in its infancy at discovering). Logic (see also the SEP) is both an art and a science. You cannot lash togther a guess with a fact and call it an induction. You cannot be uncritical. Induction is what it is, it has a nature, and you form a true and proper generalization only when you obey that nature.