Here I address, one after the other and in good order, each of the 5 failings of paleo, according to Darrin Carlson (blogpost published a few days ago in Free the animal).
Concerning knowledge, paleoanthropology & the paleo diet (the first failing : we don’t really know what our ancestors ate, therefore we can’t use paleoanthropology to guide us in our dietary choices)
First, the argument as it is described by Darrin Carlson is ambiguous. Is it an epistemological/psychological problem ? or an ontological problem ? Is it a problem with the way we build our knowledge (the way we obtain our data, analyse it and interpret it) ? Or is it a problem with the data (not representative, damaged by the time, incomplete, etc) ? Whatever it is, we can address it.
If it’s an psychological/epistemological problem, Darrin’s statement is that we do not have the adequate tools to know with 100% certainty what we ate during the Paleolithic period.
- If he uses the 100% certainty with a psychological undertone, it means that certainty is a property of belief where the subject thinks that his/her belief is not amendable or is incorrigible. But we’re dealing with scientific truth, not about opinions. Is not science about being able to find counter-evidence, counter-argument ? With 100% certainty, science disappears, enters the dogma era. Do we want paleofitness and diet to be ruled by dogma ? As far as I’m concerned, I know what my answer is.
- If he uses the 100% certainty in an epistemic way, it means that the belief possesses the highest epistemic status. There are several definitions for this approach : indubitability, no mistake being possible, justification to the highest degree. The first two are psychological, so they fall upon my precedent remark. The problem with this approach is that it is very restrictive. Only some mathematical truths, that we know we can exhibit each section of the demonstration, pertain to that category where every part of a theory is known to be true. But paleoantropology does not demonstrate anything. It goes like any experimental science, from hypotheses to confrontation of hypotheses to evidence and data. Thus, there could no more than corrobated hypotheses. We are dealing with defeasible theories (under better interpretations or precedently unheard of data), not with mathematical demonstrations. In other words, it’s not a failing because it’s never been its aim to produce 100% certainty. We just can’t expect to find 100% justified truths from paleoantropology because it’s not its goal and it’s not in its power. 100% epistemic certainty is simply not relevant.
If it’s an ontological problem, Darrin’s statement is that we do not possess the adequate and complete picture of what our paleolitic ancestors ate : our findings are too small, damaged, etc. Indeed, we don’t know if we have the whole picture. But more than that, we don’t know if we don’t. An agnostic posture is maybe healthier. Caution is the keyword in paleoanthropology : make no more assumption that what can be obtained from interpretation of accessible data, but no less. What we think we know is reliable, because it’s grounded on very carefully analyzed data ; but for the other part, we really don’t know and won’t venture on that highly slipperey ground. What I mean is that we don’t know if we have a good picture, but each piece of the puzzle we have is quite good.
Second, the section of the argument when Darrin states that we don’t have compelling enough data on paleoanthropology to advice people to go paleo, may be flawed. The problem, according to Darrin, arises when we try to apply paleoantropology’s knowledge about our ancestors to build a contemporary scientifically justified paleo diet. It’s the classical Hume’s problem. We cannot go from « that’s the way it is/it was », « that’s the way we ought to do it ». It’s true, we can’t. It’s an unlogical leap of faith. But why would we want to derived logically the paleo diet from paleoantropology ? I think we have to consider what exactly are the relationship between paleoanthropology and the paleo diet. Is paleo diet derived from paleoanthropology, like electronic and computing technology are derived from first order logic ? or, like quantum optics are derived from quantum mechanic ? No it’s not. Why ? Because paleoanthropology’s ability to make prediction is limited by its topic : what happened a long time ago and had disappeared. A paleoanthropology expert can make predictions about features of humanity in the past, not in the present or future. The laws of paleoanthropology have a very precise range. Quantum physics is about what was, what is, and what will be. Logic is about what is sound according to a certain system of formal derivational rules and axioms, whatever are the other conditions. A quantum optics expert will use general laws, relevant for many and many conditions, to make predictions and explains aspects of optics. She/he will consider objects of optics to be in the range of the general laws formulated by quantum mechanics. The same goes for an electronic expert. Is it the case in paleoanthropology ? Are paleoanthropological law’s structure sufficiently abstract to consider that nowadays humans fall in its domain ? On what ground ? I think a paleoanthropology expert is only able to make prediction about the past of humanity, about what we were 3 millions years to 10 000 years ago. Biologically (the interbreeding criterion), we didnt change much, but from a evolutionary point of view (divergence of some members increased by isolation from the main population), we did change a lot. Thus the problem is not that we don’t know enough about our ancestors, but that it cannot tell us what we are now and what we should do. It’s simply not relevant, we are out of range in some way. A paleo diet is not an application of laws about the past human nature to nowadays human. It’s a diet grounded on, among other things, paleoanthropology, which means that a paleo diet borrows results of researches about what was humanity to offer arguments and evidences in its favor. A paleo diet expert is like judge who uses paleoanthropology researches (among others) to ground his decision.
Conclusion : it’s not paleoanthropology’s purpose to tell us what we should do, but it can help us to ground our decision to go paleo. So no failing, but maybe a disappointment for those who expect paleoanthropology to be the new Bible.
Concerning relativism and the Paleo diet (failing 2 : there is a plurality of paleo diet, therefore there is no One paleo diet).
First, formally, the argument is flawed. You cannot entail from the fact that there is several paleo diet, that none of them is better than the others. It’s like saying that there are many recipes in this world, consequently all of them must share the same gastronomic properties. Indeed, it’s conceivable that among the numerous variant of paleo diet, one (or some are) is better than others. We cannot exclude this possibility simply because the criterion to identify this better diet isn’t currently clear. The relativist argument doesn’t hold.
Second, of course, there is no ONE paleo diet, because there is no paleolithic diet, but only a paleolithic lifestyle, the way humans exploited their environment with specific tools and technology and interacted with each others. It’s a form of life where exploitation of any environment is made by specific tools and technology. Nothing else. Yet environment ressources differ enormously one to another, this is why the resulting diets are not unified (even if the same technology was applied in each context). The result were different if you were in Ethiopia or if you had migrated to Denmark or Australia. But does that mean that each resulting diet was equally adequate for the metabolism of the humans exploiting the ressources of different environment ? It’s very far stretched conclusion. I wouldn’t go that far, because they may have mutated to adapt to new environment constraints. On the other hand, we know (studies show) that differences in diet have impact on health. So it seems to me that it’s highly probable that some paleo diet are better than others, even if the question of identification is still without clear answer.
Conclusion : there is no magic diet for humans, but some are probably better than others.
Concerning the speed of human evolution (failing 3 : we have evolved since the paleolithic, thus we can incorporate neolithic food in our diet).
Indeed, we did evolve and still are. But that’s not the point of John Hawks’ study. First, we have to distinguish between mutation (a change in a genome) and selection (a nonrandom process by which a biological trait is fixed and dominant in a population), and its link to growth of population : the whole point of his study is that there is a correlation between the growth of the population and the rate of mutations. And the higher the rate of mutation, the higher is the probability to find adaptive mutations in a new environment. But growth of population isn’t a selection tool. Thus the fact that we mutate a lot doesn’t necessarily imply that adaptive mutations are already fixed (dominant) in our species.
Second, there is the constraint of selection/mutation exclusivity to consider : the more selection you have, the less mutation you can have (when the members of species reach the optimum adaptation to their environment, then the space for mutation diminishes). Thus, with a new environment (opening of Neolithic era), and the sudden growth of population, we can assume the gross rate of mutations in human species has increased, and that it is highly probable adaptive mutations were selected. The study shows a huge increase in mutations, which means that the human body wasn’t at all ready for this kind of new lifestyle, because it was optimally adapted to paleolithic lifestyle and environment. The room left to mutations was very narrow at this point. We have to bear in mind that, even if our mutations rate is 100 times higher than during the paleolithic period, Hawk’s study’s range, is millions of year. The neolithic revolution began only 10 000 years ago, which means that we may not have finished adapting to the neolithic revolution, which happened not a long time ago, because it’s too short a time i) to produce several pools of populations across the world who offer the adaptive mutations ; ii) to make this adaptive mutation the dominant trait. And I’m not even talking about our modern, industrialized diet (there is no point to kid ourselves, what we eat today, even if we are careful, are domesticated species of wild plants and animals. Even if you own your farm, you raise cattle, not aurochs. The same goes for grains, legumes and dairy). Modern industrialized and processed food appeared only a few decades ago, even if we are adaptating very fast, we are outmatched. Maybe a few of us have mutated, but the advantageous genes cannot be dominant at this hour.
Third, maybe some pools of human populations have evolved to adapt to a neolithic lifestyle and diet. By this I mean that adaptation to the neolithic lifestyle is or in phase of being dominant in certain human populations. Darrin is cautious in this paragraphe, when he writes that, depending on our ethnic roots, some of us may have adapted to live the neolitic way. But we don’t know who. What we do know is that real-life persons’ health is at stake. And I think it’s highly ethically dubious to encourage people to play with their health, just because of the intuitive idea they have about their ethnic roots.
Conclusion : we all evolved to live the paleolithic way (with variant according to the difference in the environment), some (who ?) of us have also evolved to live the neolithic way, a fistful of us may have also mutated to live the industrialized way.
Concerning nature (failing 4 : we cannot claim that something is good because it’s natural, therefore we cannot claim i) that the paleo diet is good because it’s natural ; ii) that the produce of the neolithic diet and of our modern diet is inherently healthy or unhealthy)
First, failure 4 mixes « naturalistic fallacy » (an expression coined my the philosopher G. M. Moore to discuss a metaphysic argument in ethic) and « appeal to nature » (a way to use nature in the premises in an informal argument). The purpose of Moore’s argument is to show that there is no clear definition of the term « good », and that it cannot be reduce to the of sensation of pleasantness (see Principia Ethica, §10sq). The purpose of the appeal to nature’s argument is to justify a idea, a value, a behaviour, by an appeal to nature ; or to criticize an idea, value or behaviour by its « unnaturality ». An appeal to nature falls under the fallacy of relevance, as it is described by Darrin.
Second, I don’t see the point of this tour de passe-passe, this rhetorical move. Expressions that can entail another expression necessarily salva veritate are really rare, philosophers doubt they are any. But the problem with Darrin’s statement is that it leads us to a dead-end, then leaves us here with no answer concerning the problem of the relation between paleo and nature. Why it is so that processed food aren’t inherently unhealthy or healthy to us ? that neolithic food aren’t inherently unhealthy or healthy to us ? Simply because what is healthy/unhealthy is determined by the cost/benefits relation in an environment/organism interaction. For me, Darrin is tackling the problem from the wrong side : it’s not « Paleo is natural, thus we have to go paleo », which is, as Darrin pointed it, a fallacy ; it’s « Nature was and is still in some ways paleo, thus we can go paleo ». And by nature, I mean the way humans interacted with a precise of state of environment. Paleo was and is partially still a state of nature, but nature isn’t a state of paleo, that is why you cannot entail that something is good because it’s paleo, or not good because it’s not paleo.
Third, the argument is flawed. It states that, because of the fallacy of the appeal to nature, we cannot say that neolithic and industrialized food are inherently healthy/unhealthy. We cannot tell that they are inherently healthy/unhealthy for the reason I exposed before. But I think we do can tell whether they are healthy or not relatively to our organism, because we don’t always need an appeal to evolution to know that something is good/bad for us. Darrin’s argument is a kind of strawman : it assumes that in some way, hypothetically, there exists a knowledge of the absolute quality of food, then refutes it. OK. But, in what way does it concern us ? Do we need this type of knowledge ? If we are talking about our health, we are talking about the health of members of the human species at some point in history. Dietary knowledge about health is always a relation between the ingerable things and a metabolism in a certain state.
Conclusion : don’t make a strawman to make up false failing of paleo, find the true weaknesses and address them.
Concerning nutrionism, science and individual intuition (failing 5 : the science of nutritionism is young and foolish, it may not be the best way to ground the paleo diet)
Darrin Carlson advises us to not let scientific studies to be the only guide of our diet. But see the following extracts :
« As it turns out, recent scientific evidence suggests that, not only have we been evolving since the advent of agriculture, we are doing so at a rate that is about 100 times greater than during the Paleolithic! […] From the standpoint of diet, it suggests that many of us, depending on our ethnic roots, should expect to handle the Neolithic foods of dairy, grains, and legumes much more effectively than others. » (From failure 3.)
« It makes a ton of intuitive sense that foods new to our diet are detrimental to our health. But from a scientific perspective, this observation is only the first part of the scientific method: formulating a hypothesis that must then be tested. » (From failure 4.)
I totally agree with Darrin concerning the fact that we should use a cross-disciplinary approach when it comes to build our diet, because some inadequacies may be corrected that way. What I don’t agree with is his « condemnation » of nutritionism, then its generalization to science. I’m not opposed to the idea that we can balance sciences’ suggestions by using our own personal experience, but I find Darrin's use of science to back up some of his remarks (as in the extract), then his critic of science, and finally his advice that sometimes we have to trust science and sometimes we don't, without really without really telling us when we should and when we shouldn’t use science, a very disturbing moove. I don’t see any failure in that, except Darrin’s failure to exhibit his criterion to chose between useful and wacky science. Nutritionism is young, consequently we cannot trust it ? What kind of argument is this ? It has to be stronger than this. Imagine the consequences of this argument in other contexts ! If nutrionism is scientific, it must answer to the standards of scientific and experimental research, which prevent the « finding » of unsound results. If we have to select between useful and wacky science, we need a good and clear criterion. Philosophers have debated for hundreds years about this and cannot find a satisfactory criterion. Darrin leaves us with our intuition. But intuition and observation of intution have to be trained. What about for those who didn’t train ? And sometimes trained intuition fails us. No, we need a collective, shared criterion for that. Our intuition needs to be balanced. And it’s not paleo’s role to tell us when science is whacky or sound.
Conclusion : some bad news : i) Paleo is not God, it cannot make a wacky theory into good science. But we already knew that ; ii) we don’t know yet how to distinguish good from bad science, but thankfully the standards for sound science are more and more selective and reliable, thus science can partially guide us in our choices.
Coming back from the future to the present of paleo
I have no great insights about the future of paleo. But some things worry me :
- Paleo is a lifestyle, not a diet. We can’t strictly eat paleo for a lot of reasons, we can only emulate it. But the diet is not the whole point of paleo, it’s about being adapted to our environment, whether be it social, physical or metaphysical. And it’s different than eating more steacks in a week.
- Paleo is about building ethically, morally, physically fit and balanced individual, not following gurus. It’s good to follow advices of people more advanced than us in that path. But if it goes against your ability to personally build your life, drop it. Follow trainers times to times, but take yourself in charge all the time. More and more gurus will come in that area, so beware.
- Paleo is about finding happiness, not burdened yourself with constraints or punished yourself for what you think are past errors. Paleo can change your life, this change can be powerful, but you have make peace with what you are and what you did. Don’t let the comparison between your current paleo state crushes what you think you were, I’m sure you did great things.
- Paleo is about finding what (I’m not saying who, that’s a whole other thing) we are as a species and as an individual, not about erudition. Paleo is an interesting topic and it’s good to study the past and present of our species. But Paleo is a tool, and only a tool. If the tool becomes more important than the task itself, it’s time to get some perspective.