|Hypothesis and Uninformative Tautology? Source: CDC|
"Since the 1950's, the conventional wisdom on obesity has been simple: it is fundamentally caused by or results form a net positive energy balance––another way of saying that we get fat because we overeat. We consume more energy than we expend."
Directly under the heading "Energy balance hypothesis" he goes on:
“Despite its treatment as gospel truth, as preordained by physical law, the energy balance or overeating hypothesis of obesity is only that, a hypothesis.”
Thus, he appears to maintain that the idea that organisms gain weight because they consume more energy than they expend is only a hypothesis. This implies that in his view, it is hypothetically possible for an organism to gain body mass without sustaining a net positive energy balance.
Maybe it is also possible for me to gain in wealth without sustaining a net positive income balance? Wouldn't it be great if you could grow your bank account while spending more than you earn? Did the editors of the BMJ really believe that Taubes discovered some new laws of nature and mathematics?
To understand why the energy balance equation is not a hypothesis, we need to understand 1) the concept of hypothesis and 2) the first law of thermodynamics.
A hypothesis is a speculative explanation for a phenomenon, generally based on observation of the behavior of the phenomenon in question. A hypothesis is potentially falsifiable.
For example, based on observations, I may speculate that diets containing 25% plant protein are more satiating than diets containing 5% plant protein. I can state all hypotheses in “maybe” statements, e.g. “Maybe diets containing 25% protein are more satiating that diets containing only 5% protein.” I can then construct an experiment to test my hypothesis. The results of the experiment may confirm or cast doubt on my hypothesis.
Thus, if the energy balance equation is merely a hypothesis, scientists would state it as follows:
"Maybe changes in body mass equal the difference between net energy intake and net energy expenditure."
In addition, if this is a hypothesis, as claimed by Taubes, scientists should be engaged in attempts to test or refute it, and it should be possible to create an experiment which could produce a result that would refute it.
Regarding the first alternative, it is quite obvious scientists do not use the energy balance equation as a “maybe” statement. As a matter of fact, scientists state the energy balance equation in mathematical form as follows:
ΔEbm = Ei – Ee
Where Ebm is the energy stored in body mass, Ei is energy intake, and Ee is energy expenditure.
Translated to prose, this equation states:
Any change in body energy stores is equal to energy intake minus energy expenditure.
Furthermore, no scientist is spending his/her time testing and attempting to refute the energy balance equation. On the contrary, this equation is assumed and used as the very basis for investigating and shedding light upon the various processes that affect net energy intake and expenditure.
Now, someone might say that scientists are supposed to question every thing and not assume anything. So the question arises, do scientists need to test this energy balance equation before assuming and using it in their investigations?
To answer this question we need to understand the law of conservation of mass and energy.
The conservation law of thermodynamics states that neither energy nor mass is created or destroyed in any physical process. Although this law may look like a hypothesis –– which would be stated “maybe energy and mass are conserved in all physical changes” –– in actuality it is not potentially falsifiable because it is in principle impossible for any experiment to refute the law.
Refutation of this law would require an experiment during which some bit of either energy or mass was ether created out of nothing –– that is, independent of change in any other phenomena –– or destroyed without residue or leaving any trace––that is, again, independent of changing any other, related phenomena. I would have to either produce or annihilate some thing without transforming any other thing.
It is in principle impossible to create or observe such an event, because it is the very nature of things (phenomena) to be dependent upon and derived from (transformations of) other, related things. A observable thing that arises or disappears independent of changes in other things is logically impossible and in principle unobservable.
Basically, any appearance can be viewed as a type of increase, whereas any disappearance can be understood as a species of decrease. It is impossible for an increase (appearance) to occur without a corresponding and related decrease (disappearance), just as it is impossible for a mountain (increase) to appear without the simultaneous appearance of a valley (decrease). It is also impossible for a decrease to appear in one location without a corresponding increase in another. (Buddhist thinkers call this the principle of dependent origination).
It is impossible demonstrate something arising out of nothing because to do so we would have to first create or demonstrate a field of nothingness. Such a field would have no characteristics or features, margins, size, shape, or location. Consequently, it could not be an object of perception. Since it is impossible to see, hear, smell, taste, or touch nothing, it is also impossible to show some thing (mass or energy) arising out of nothing.
Further, any observation involves changes in the observer's perceptual apparatus, hence it is in principle impossible for for something to appear (be noticed) without the appearance of that thing causing changes in other things (at a minimum, the perceiver's sensory organs).
This leads to the most important point that the law of conservation of mass and energy is an essential foundation to scientific knowledge of phenomena. If phenomena did not conform to the conservation law, no scientific knowledge of phenomena would be possible. If things popped into and out of existence at random, it would be impossible to account for or control changes in phenomena. This law simply describes the basic, unalterable nature of phenomena that makes scientific knowledge and technological control of phenomena possible.
Now, the energy balance equation is nothing more than a specific restatement of the conservation law.
As a matter of scientific principle, if the energy balance law did not apply to phenomena, it would be impossible to track flows of energy and mass in the environment or body, because energy or mass could suddenly come into existence or disappear into nothingness at any point in time. From this it would follow that it would be impossible to control the flow of energy and mass in the environment.
Refutation of the energy balance law would require an experiment in which a change in body energy stores is produced without an equivalent change in difference between energy input and expenditure. In other words,1) an experiment wherein people accumulate body energy stores while while energy intake is either equal to or less than energy expenditure; or 2) an experiment wherein people lose body energy stores while energy intake is either equal to or greater than expenditure.
For example, an experiment where people fast and yet either maintain or gain weight; or an experiment wherein people consume more calories than they expend, yet either maintain or lose weight.
From this it follows that in claiming that the energy balance equation is a hypothesis, Taubes conceptually allies himself with breatharians who claim that people can maintain body weight and health without food intake. Apparently, the editors of the British Medical Journal consider the reasoning processes of the breatharians worthy of scientific attention. They are apparently more gullible than the producers of 60 Minutes who put the scam artist to the test.
Taubes seems to be suggesting on one hand that "maybe" fasting, undereating, or eating foods rich in carbohydrates activates hormones or "lipophilic adipose tissue" in such a way that people will gain weight despite low food energy intake.
On the other hand, Taubes appears to venture the hypothesis that "maybe" obese people can starve the "lipophilic adipose" and lose weight by consuming lots of fat and calories. Strangely he seems to think that "lipophilic" i.e. fat (lipo-) loving (-philic) adipose doesn't love dietary fat.
Makes perfect sense, right?
What a magical world he lives in. Applying his reasoning to other phenomena, I venture the following hypotheses:
Maybe the best way to stay optimally hydrated is to limit all water intake (including food source water) as much as possible, and dehydration is caused by drinking water.
Maybe the best way to accumulate wealth is to spend every penny one earns, and the best way to go broke is to save more than you spend.
Sarcasm aside, in stating the energy balance equation, no scientist is hypothesizing that the “change in body energy stores” is “the difference between energy intake and energy expenditure.”
On the contrary, we use this equation to guide investigation and control of changes in body mass. If someone’s body mass goes up, we look for increases in energy intake, or decreases in energy expenditure. If someone’s body mass goes down, we look for decreases in energy intake, or increases in energy expenditure. If we want to reduce body mass, we reduce energy intake or increase energy expenditure; if we want to increase body mass, we increase energy intake or decrease energy expenditure.
In other words, we use this equation the same way we use the second law of motion––F=ma–– to understand or control the motions and impacts of objects. This equation tells us how to increase or decrease forces by manipulation of mass or acceleration, just as the energy balance equation tells us how to increase or decrease body mass by manipulating energy intake or expenditure.
Taubes contends that “the energy balance notion has an obvious flaw: it is tautological. If we get fatter (more massive), we have to take in more calories than we expend––that’s what the laws of thermodynamics dictate––and so we must be overeating during this fattening process. But this tells us nothing about cause.”
In this statement, Taubes shifts from calling the energy balance equation a hypothesis to saying that it is dictated by the laws of thermodynamics, contradicting his own claim that it is a hypothesis. But now he thinks he can dismiss it because it is a meaningless tautology.
So now we need to understand tautology.
A tautology is a statement that is true under all circumstances by virtue of its logical structure.
Before going any further, I want to point out that Taubes calls energy balance both a hypothesis and a tautology, but it is impossible for any statement to be both a hypothesis and a tautology, because a hypothesis proposes a possibility, and may be refuted, but a tautology is true under any and all circumstances, so can never be refuted.
Anyone who calls the energy balance law both a hypothesis and a tautology reveals an incorrect understanding of both types of statements and a very poor grasp of fundamental principles of logic, epistemology, and science. Anyone who allows someone else to publish a paper in BMJ with this fundamental contradiction is similarly lacking.
Some frequently discussed examples of tautology are:
This mystery is unsolved.
A bachelor is an unmarried male.
Red is a color.
It is either raining outside, or not raining outside, right now.
I think, therefore I am.
Now, let’s take a look at these four examples, asking, are these all tautological for the same reason? The answer is NO.
The first example–”This mystery is unsolved”–is called a rhetorical tautology. Since a mystery is by definition unsolved, the statement is true under all circumstances and provides no new information.
“A bachelor is an unmarried male” is tautological by definition. We don’t need to refer to experience to confirm this statement, by which I mean that we don’t confirm it by examining unmarried males, in an attempt to confirm that every one of them is a bachelor. This statement is a tautology because by convention, we assign the same meaning to the word “bachelor” as to “unmarried male.” We could just as easily decide to henceforward use the word “pixidingdong” as synonymous with “unmarried male.”
“Red is a color” is tautological because red belongs to the class “colors.” Therefore, the statement is not informative because saying red is a color does not give new information about red. Notice that this is different from “A bachelor is an unmarried male” because while ALL bachelors are unmarried males and vice versa, red is a color, but not all colors are red.
“It is either raining or not raining outside right now” is true under all circumstances because it is a statement of jointly exhaustive and mutually exclusive alternatives. The general form of such statements is "A or not A."
Finally we get to Descartes’s famous dictum “I think therefore I am.” This has also been called a tautology on the grounds that the statement “I think” is said to already include the statement “I am.” In other words, it is claimed to be without information because if I say “I think” I am already saying “I am.”
However, people who make the claim that this statement provides no information seem to have missed something very important. How does one know the meaning and relationship of the statements “I think” or “I am"? Does one merely look it up in a dictionary? Did you have to be taught that “I think” includes “I am” the way that you had to be taught that “bachelor” means “unmarried male,” or “color” includes “red” or “mystery” means “unsolved”? Is “I think” arbitrarily related to “I am” as “bachelor” is to “unmarried male”? Is “I think” a species of “I am” as “red” is of “color”?
It should be very clear that meanings of "I think" and "I am" are neither arbitrarily derived nor arbitrarily related like "bachelor" and "unmarried male."
Try as one may, it is impossible to give a meaningful lexical definition of “thinking” or “being.” These concepts derive their meaning directly from our direct experience of being and thinking. Moreover, one knows that “I think” includes “I am” not by mere analysis of terms, nor because someone told us so, but by direct experience.
Further, Descartes was not a stupid man who spouted uninformative bullshit. He did make some mistakes, but unlike those who attack his statement as a trivial tautology, he was astute enough to see that the statement “I think, therefore I am” conveys profoundly important information about the structure of experience and the relative ontological status of one’s own self in comparison to the objects one observes, as well as the vast difference in epistemological status between this statement and statements about the observed world, like "The sky is blue."
Descartes saw that "I think therefore I am" conveys the important fact that one’s own existence is certain beyond doubt, because one’s existence is the necessary condition for one’s doubting (thinking); whereas the statement "The sky is blue" is not beyond doubt, and in fact is contingent upon a certain condition of one's eyes. By the latter statement I simply mean that if we had eyes with some different conditions, the sky would not appear to us as what we now call blue.
Hence, although it is in a sense correct to call “I think, therefore I am” an analytical truth or tautology, this statement is very, very different from “the mystery is unsolved,” “a bachelor is an unmarried male,” “red is a color,” or “A or not A.”
I discuss this last example extensively because it shows that some so-called tautologies are not trivial statements, but in fact convey information about the fundamental structure of our experience.
Now, as I stated above, the energy balance concept is actually a physical science equation.
ΔEbm = Ei – Ee
If this is a tautology, then so also are other such equations, such as:
E = mc2
F = ma
In the case of “a bachelor is an unmarried male,” we arbitrarily establish an equivalence between the word “bachelor” and the status “unmarried male.” But when Newton formulated the equation “force equals mass multiplied by the acceleration” he was not arbitrarily defining “force” as “mass x acceleration,” and Einstein did not define E as mc2 on a whim. On the contrary these scientists discovered these equations only after very hard work attempting to understand the behavior of phenomena.
Further, neither F=ma nor E= mc2 is a statement of class inclusion like “red is a color.” Nor do these equations state jointly exhaustive alternatives, like “it is either raining or not raining outside right now.”
Someone might try to argue that in physics the word “force” has the same meaning as “mass x acceleration” and therefore that the equation F=ma is a tautology. Let's accept this. Would this deprive this equation of its immense scientific importance and power?
In fact, each of these equations mathematically expresses the behavior of phenomena and enables us to understand and control the behavior of phenomena.
|Source: Physics UMD|
For example, F=ma states that the existence and magnitude of any force depends upon i.e. arises from a mass and acceleration. Knowledge of this tautology enables us to answer questions.
If I ask the question, “If I drop a feather and a boulder from the same height to the earth, why does the feather hardly disturb the earth while the boulder leaves a crater?” The second law of motion provides the answer that although both feather and boulder are subjected to the same acceleration, the boulder hits the earth with more force because it has a greater mass.
If I ask the question, “How can I increase the safety of resistance exercise for the joints?” the second law of motion provides the answer: Reduce the forces to which you subject the joints by reducing the acceleration applied to the resistance. In other words, gradually apply force to the resistance when starting movement, and at turnarounds in the range of motion, ease into and out of the ends of the range of motion, never yanking on the resistance or letting it drop.
In his BMJ article, Taubes wrote:
“If we get fatter (more massive), we have to take in more calories than we expend––that’s what the laws of thermodynamics dictate––and so we must be overeating during this fattening process. But this tells us nothing about cause. Here’s the circular logic:
Why do we get fat? Because we overeat.
How do we know we’re overeating? Because we’re getting fatter.
Andy why are we getting fatter? Because we’re overeating.
And so it goes, round and round.”
Is this circular reasoning? No. Circular reasoning occurs when someone makes an argument that includes the dubious conclusion as one of the premises. The statement "We grow fat because we overeat" is not an argument, nor is it logically reducible to either "We grow fat because we grow fat" or "We overeat because we overeat."
To clarify, by Taubes's reasoning the statement "My car starts because I turned the ignition switch" is circular logic, and reducible to "My car starts because my car starts" or "I turned the ignition switch because I turned the ignition switch." If he believed what he wrote, then he was at the time incapable of distinguishing a causal statement from circular reasoning. This would make it difficult for him to pass a basic logic course.
Now, suppose you went to a physicist and said:
“If I want to reduce the forces acting on my knee joints, I have to either reduce my body mass or my acceleration––that’s what Newton’s second law states––and so I must be reducing my mass or my acceleration during this force-reduction process. But this tells me nothing about cause. This is the circular logic:
Why are my knees subject to high forces? Because of high mass or acceleration.
How do I know mass or acceleration is high? Because my knees are subject to high forces.
And why are my knees subject to high forces? Because of high mass or acceleration.
And so it goes, round and round.”
Would the physicist now throw up his hands and say “Oh my stars, you have just shown that F=ma is just a trivial tautological hypothesis and circular logic!”? Emphatically not. Instead, he might say “Idiot! All you need to do is reduce your acceleration, more specifically you should decelerate as you come into contact with the earth. For example, walk with gentle steps, don’t run or jump. Or you could eat less and lose 40 pounds. What’s the matter with you?”
If you retorted with “But I want to know what will cause me to walk instead of running, or cause me to eat less and lose 10 pounds. This equation doesn’t help me” the physicist might wonder how anyone who appears to have control over his speech could not understand how to control his speed of locomotion or the trajectory of hand to mouth.
Similar to F=ma and E= mc2, in the energy balance law, we aren’t arbitrarily equating “change in body energy stores” as “the difference between energy intake and energy expenditure” in the way that “bachelor” is arbitrarily defined as “unmarried male.”
Nor are we stating that “change in body energy stores” belongs to the class “the difference between energy intake and energy expenditure” as in the tautology “red is a color.”
On the contrary, the energy balance equation expresses a natural law that describes the behavior of phenomena within a particular realm. Although it may be said to satisfy the criteria for a tautology because of the meanings of the terms, the meanings of the terms are not arbitrary but derived from and representative of a basic, unalterable feature of our experience. Hence, it is both an analytical truth and a phenomenologically grounded truth, discovered only after extensive scientific study of phenomena, not arbitrarily created. One of my mentors, physicist and philosopher of science Ramakrishna Puligandla Ph.D. correctly classifies these statements as phenomenological-analytical truths.
Far from trivial and uninformative, Newton’s apparently tautological second law of motion tells us the necessary physical conditions for manifestation and alterations of physical forces, and opened up a whole world of physics and engineering that was unknown before Newton.
Similarly, the energy balance law It tells us the necessary conditions for change in body energy stores: a difference between energy intake and energy expenditure, and made it possible to discover the various factors that affect net energy intake and net energy expenditure.
Consequently, like all other scientific laws and equations, although the energy balance law appears analytically true or tautological, it is not trivial or uninformative, because it is grounded in the structure of our experience.
It is impossible for any statement to be both a hypothesis and a tautology.
The law of conservation of mass and energy is not a hypothesis but is true of any and all phenomena at all times and places because it is the very nature of phenomena to be dependent upon and derived from (i.e. transformations of) other phenomena.
The energy balance equation is a specialized statement of the law of conservation of mass and energy.
Not all tautologies are trivial and uninformative. Modern science owes much of its power to the discovery of natural laws which can only be expressed in apparently tautological form.
One must understand the difference between a hypothesis and a tautology, and the differences between various types of tautologies especially in regard to their origins, in order to have an accurate understanding of the principles and practice of science.
Although Gary Taubes hoped to dismiss the energy balance law as trivial and uninformative by calling it both a hypothesis and a tautology, he only thereby revealed a lack of understanding of the terms he used and of the basic principles of natural sciences.