Saturday, June 29, 2013
Perhaps the best single article I have read on the group selection debate is “Evolution ‘for the Good of the Group’”, in American Scientist, September-October 2008. It is another collaboration between the two Wilsons, E. O. and D.S. I would add that it is also a very good introduction to the general question of the levels of selection‑genes, individuals, and groups, within a population.
Group selection is one explanation for the evolution of altruism. Any time one organism (or any unit within an organism) behaves in such a way as to confer a reproductive advantage to another organism at its own expense, this is evolutionary altruism. Honey bee workers who serve the queen but do not themselves reproduce are behaving altruistically. A vampire bat who regurgitates some hard won blood to feed a hungry roost mate is another example. Many examples of altruism are easily explained in terms of deferred gratification (reciprocity) or benefit to closely related individuals (kin selection).
Group selection theory is based on the claim that some altruistic behaviors are selected for because they benefit the group without any return to the altruist whether direct (deferred gratification) or indirect (kin selection). A group with more altruists will be more reproductively successful than a group with fewer and so altruists may increase in the total population, at least initially. Increase in the total population is what we mean by evolution.
There seems to be an insuperable problem. While between group selection might well favor altruistically endowed groups, within group selection will favor the selfish over the public spirited organisms. Altruists would seem to be doomed to inevitable extinction as their selfish fellows outbreed them. In this view, which held the field for a long time, group selection is unsustainable.
However, group selection does in fact occur. Wilson and Wilson present a number of forceful examples. My favorite is the bacterium Pseudomonas fluorescens.
When this species is cultured in an unstirred broth, the cells soon consume most of the oxygen in the bulk of the medium, so only a thin layer near the surface remains habitable. A spontaneous mutation called wrinkly spreader causes cells to secrete a cellulosic polymer that forms a mat and helps them colonize the water surface. Production of the polymer is metabolically expensive, which means that nonproducing “cheaters” have the highest relative fitness within the mat; they get the benefit of the mat without contributing to its upkeep. However, if the proportion of cheaters grows too high, they are undone by their own success. The mat disintegrates, and the entire group sinks into the anoxic broth. Experiments by Paul B. Rainey and Katrina Rainey have shown that the wrinkly spreader trait is maintained in the population by group selection, even though it is disadvantageous within any one group.
This example illustrates the fact that the “free rider problem” is real. The benefits of altruism in between group selection can indeed be undone when selfish cheaters crowed out the altruists. At the same time, the very fact that mats form at all demonstrates that group selection was a powerful force in the evolution of this microbe. Wrinkly spreader can only be maintained by its benefit to the community.
Obviously, what is needed to maintain group selection is some mechanism for suppressing cheating. I have no idea how this is done by bacteria but Christopher Boehm has a good idea how it is done among human hunter gatherers. He argues in Moral Origins that social selection (reproductive benefits that result from a reputation for altruistic behavior) and sanctions against bullies (free riders) functioned to protect altruists from cheaters.
Human beings are extraordinarily capable of altruism toward unrelated individuals. Explaining this is a big challenge for evolutionary theory. Boehm considers a number of explanations that are current in the scholarship. He doesn’t reject them, but argues that some of them work only when cheating is suppressed by the mechanisms mentioned above.
In Plato’s Gorgias, Socrates argues that justice is analogous to medicine: it is a response to dysfunction in the social body. I am inclined to think that the theory of group selection is beginning to uncover something like the Platonic idea of justice. It may be that retribution is something that shapes all life on earth.
Friday, June 21, 2013
Jonathan Haidt’s fascinating survey work on the moral foundations of politics identifies a number of dichotomies that define the political culture in the U.S. These are care/harm; fairness/cheating; liberty/oppression; loyalty/betrayal; authority/subversion; and sanctity (or purity)/degradation. Haidt argues that what distinguishes the left and right in America is which of these dichotomies they hold to be most important. Here is a quote that I take from an earlier blog post:
Political liberals [in the U.S.] tend to rely primarily on the moral foundation of care/harm, followed by fairness/cheating and liberty/oppression. Social conservatives, in contrast, use all six foundations. They are less concerned than liberals about harm to innocent victims, but they are much more concerned about the moral foundations that bind groups and nations together, i.e., loyalty (patriotism), authority (law and order, traditional families), and sanctity (the Bible, God, the flag as a sacred object). Libertarians, true to their name, value liberty more than anyone else, and they value it far more than any other foundation.
One interesting thing that Haidt notes is that conservatives are much better at guessing what values liberals hold than vice versa.
I am guessing that liberals may be just as bad at guessing what they themselves believe as they are at guessing what conservatives believe. As I recall, the further to the left you go, the less emphasis you get on sanctity/degradation. Most on the left, I suppose, would be uncomfortable those terms. However, anyone who pays attention to the liberal culture in America will note that they spend a lot of time, energy, and money on achieving purity.
The fair trade culture is one glaring example. I can buy a pound of “Peace Coffee” at my local coopt. Such labels as “fair trade” and “sustainable” are nothing if not certifications that the purchase and consumption of a product is kosher. A couple of articles illustrate the character and the absurdity of this culture of purity.
Judith Shulevitz at The New Republic exposes the “cleansing” fad as a quazi-religious bit of numbskullery.
One afternoon last month, I made a nervous visit to the office of Ghiora Aharoni, an Israeli sculptor and architect of some renown. The awkward part was that I hadn’t come to interview him about his work. I was there to hear about his gut. He had just finished a 21-day cleanse, the kind with supplements, protein shakes, and endorsements by the likes of Gwyneth Paltrow. (It’s called the Clean Program.)…
What draws sophisticated and healthy people like Aharoni’s friends to commercial quasi-fasts? Cleanses, whether they last a day, a weekend, or three weeks, and whether they consist exclusively of fruit and vegetable juices or just a severe restriction of solids, are quickly becoming a part of what you might call the cosmopolitan diet, consumed in the more urbane sectors of New York and Los Angeles and Austin or wherever you find Whole Foods–levels of gastronomic consciousness and sufficient disposable income…
Aharoni and others made it clear that they fast for more than the mere improvement of their psycho-physiological wellbeing. Aharoni described his cleanses as “journeys” or “traveling while staying at home,” phrases that echoed (to me, at least) the visionary transports achieved by fourth-century Christian desert ascetics and medieval holy women. As it happens, these saints starved themselves only partly out of piety; rejecting food, they also rejected a church committed more to institutional growth than the extremes of religious experience. Another explanation I heard was that people cleanse out of a sense of shame: Their eating and sometimes their lives feel out of control. In the past, this same feeling might have provoked atonement, particularly for the deadly sins of greed and gluttony. These new cleanses are “religion without theology,” my friend Ruby quipped.
That is how I see it. Cleansing is religious fasting without the theology but not without the superstition. The ubiquity of such practices in various religious traditions testifies to the psychology need that it attempts to satisfy. However, the practice makes a lot less sense without the theology. It’s one thing if God or my recommends a diet. But Gwyneth Paltrow?
A second article in The Atlantic by David H. Freedman exposes the locavore/anti-processed food cult to withering scrutiny. Freedman is chiefly concerned with America’s big health problem, which is big Americans.
He goes after natural food gurus Michael Pollan and Mark Bittman. They peddle the tale that the food and restaurant industries are making us fat. If only we would stop eating processed foods and eat only something our great grandma would recognize can we burn off the pounds and be healthy again. Behind them is the establishment press and a range of commercial enterprises (the New York Times and Whole Foods figure prominently).
Thousands of restaurants and grocery stores, most notably the Whole Foods chain, have thrived by answering the call to reject industrialized foods in favor of a return to natural, simple, nonindustrialized—let’s call them “wholesome”—foods. The two newest restaurants in my smallish Massachusetts town both prominently tout wholesome ingredients; one of them is called the Farmhouse, and it’s usually packed.
A new generation of business, social, and policy entrepreneurs is rising to further cater to these tastes, and to challenge Big Food. Silicon Valley, where tomorrow’s entrepreneurial and social trends are forged, has spawned a small ecosystem of wholesome-friendly venture-capital firms (Physic Ventures, for example), business accelerators (Local Food Lab), and Web sites (Edible Startups) to fund, nurture, and keep tabs on young companies such as blissmo (a wholesome-food-of-the-month club), Mile High Organics (online wholesome-food shopping), and Wholeshare (group wholesome-food purchasing), all designed to help reacquaint Americans with the simpler eating habits of yesteryear…
If the most-influential voices in our food culture today get their way, we will achieve a genuine food revolution. Too bad it would be one tailored to the dubious health fantasies of a small, elite minority. And too bad it would largely exclude the obese masses, who would continue to sicken and die early. Despite the best efforts of a small army of wholesome-food heroes, there is no reasonable scenario under which these foods could become cheap and plentiful enough to serve as the core diet for most of the obese population—even in the unlikely case that your typical junk-food eater would be willing and able to break lifelong habits to embrace kale and yellow beets. And many of the dishes glorified by the wholesome-food movement are, in any case, as caloric and obesogenic as anything served in a Burger King.
In other words, the whole whole foods movement is very well designed to satisfy the desire of a prosperous elite for purity but poorly designed to address the real problem of obesity and hopeless when it comes to meeting the needs of those who most suffer from it.
Freedman rigorously establishes three points.
1. Much of the food peddled by the food revolution is “obesogenic as anything served in a Burger King.”
2. The food peddled by the food revolution is too expensive both in money and in time to be available to the obese masses.
3. The one institution in America that can effectively address the problem is the fast food industry.
The last is the most provocative, but that is what The Atlantic is for. I would add that he is obviously right. No one is better than McDonalds or Carl’s Junior at making food cheaply and quickly available and no one is better at marketing food to the masses. Getting the industry to move in that direction is not so hard. It is already happening, as Freedman demonstrates.
The desire for purity is a basic human instinct but it is not always a reliable guide. Modern liberalism has always been an elitist business, yet it purports to care about the many unwashed. If it is really to make good on that purpose, it will have to take a good hard look at itself. Don’t hold your breath.
Wednesday, June 19, 2013
To a man who makes shoes, the whole world is made of leather.
That proverb, Chinese in origin if I remember correctly, came to mind tonight as I read more of Addy Pross’ What is Life. This is one of those beautiful little books that bare the soul of a complex science to amateurs like me. Pross clearly intends to answer the question in a reductionist fashion. Biology, he dares to say at one point, is just another branch of chemistry. Well, the whole world is made of chemicals. Is biology really reducible to chemistry? No.
In chapter 4: ‘Stability and Instability’, Pross gives us a tour of basic chemistry. Chemical reactions move “downhill,” i.e., from states of higher free energy to states of lower free energy. Sometimes, I gather, they have to get over a “hump,” and in those cases a catalyst is required.
To employ my own analogy, an avalanche occurs when an unstable sheet of snow begins to slide downhill. The catalyst may have been some fool yodeling. The result is a ton of snow on top of a group of helpless skiers, at which point the situation is distressingly more stable than the original state.
Similarly, a mixture of hydrogen and oxygen gas is higher in energy than water. It requires a spark (the catalyst) to get the former to combine into the latter, but once the combination has happened water is relatively stable. Good thing, that. Two cheers for the second law of thermodynamics.
Pross then makes a distinction between two kinds of stability: static and dynamic. Water molecules are statically stable. Once formed, a molecule of water remains materially what it is pretty much forever. A river, by contrast, is dynamically stable. The Thames River has been flowing, he tells us, for around thirty million years—longer than there has been an England. Yet the water in it is constantly renewed. As Heraclitus famously observed, you can’t step in the same river twice.
Self-replicating molecules (e.g., RNA) are capable of achieving dynamic stability. They form and decay by a constant exchange of basic building blocks. In one experiment, more robust RNA chains emerged from less robust versions. All populations of living organisms achieve some measure of dynamic stability. Cyanobacteria have been in business for more than two billion years! That makes geography look short sighted.
Pross goes all in by arguing that the stability achieved by such populations of organisms is more than analogous to the chemical stability governed by the second law of thermodynamics (which just states that isolated molecular systems always go from less stable to more stable states). He proposes a version of the second law for dynamic stability:
Replicating chemical systems will tend to be transformed from (dynamically) kinetically less stable to (dynamically) kinetically more stable.
So the elegant symmetry of chemical reactions is reproduced at the level of organic systems. Thus is biology consumed by chemistry.
Color me underwhelmed. Granted, I am only half way through the book; however, it seems to me that dynamic stability just isn’t another version of static stability. It is a whole ‘nuther’ animal, as we would say down South. To be sure, everything going on in living organisms has to obey the laws of thermodynamics. Organisms, however, obey rules that are not derived from those chemical laws. The stability of populations in a given ecosystem incorporates chemical stability but it is not reducible to the laws of chemistry. Biology is a more comprehensive science than chemistry. Sorry.
Nonetheless, I am very grateful to Pross for this argument. I think that he has conceded all the ground he hoped to occupy. I also think that his dynamic stability is pretty much what Aristotle was aiming at in his treatment of the soul. Aristotle’s soul is precisely the communication of organic form over time by means of a constant exchange of matter (and I would add, energy) with the outside world. Aristotle was a vehement opponent of reductionism. Pross’ reductionism isn’t reductionism at all, thus confirming the Philosopher’s point.
Monday, June 10, 2013
One of the most brilliant essays on the history of science that I ever read was Adam Smith’s ‘History of Astronomy’. Smith explains the difference between ancient or classical astronomy and modern astronomy as a difference in metaphors. For the ancients, the central metaphor was natural growth. They thus understood the heavens as essentially biological phenomena writ large. For moderns, the central metaphor is the machine. In the course of his essay, Smith presents an account of human understanding in distinctly mechanical terms.
We want our understanding to move from the phenomena to the explanation as smoothly as possible, so we build our explanations as we would build a ramp for a rolling ball. Gaps in the ramp require the ball to jump violently from one part to another, thus creating shock. Analogously, gaps in explanation produce the shock of surprise, which is unpleasant. So we try to build a continuous set of ramps in our explanations over which the understanding can flow smoothly.
Of course, Smith’s point included a note of caution. His mechanistic account of human reason, however serious one might take it, is still just a metaphor. One cannot take it seriously, but it is brilliant nonetheless.
Tonight I read Steve Talbott’s essay “The Unbearable Wholeness of Beings”, in The New Atlantis. It is a very strong critique of mechanism in biology. Talbott argues that modern biologists use two distinct sets of terminology, one appropriate to physics and chemistry and the other to living organisms; however, they do not recognize that the two languages are distinct or bother to carefully define their terms and sort out the differences. This, he thinks, results in profound confusions.
Think first of a living dog, then of a decomposing corpse. At the moment of death, all the living processes normally studied by the biologist rapidly disintegrate. The corpse remains subject to the same laws of physics and chemistry as the live dog, but now, with the cessation of life, we see those laws strictly in their own terms, without anything the life scientist is distinctively concerned about. The dramatic change in his descriptive language as he moves between the living and the dead tells us just about everything we need to know.
No biologist who had been speaking of the behavior of the living dog will now speak in the same way of the corpse’s “behavior.” Nor will he refer to certain physical changes in the corpse as reflexes, just as he will never mention the corpse’s responses to stimuli, or the functions of its organs, or the processes of development being undergone by the decomposing tissues.
Virtually the same collection of molecules exists in the canine cells during the moments immediately before and after death. But after the fateful transition no one will any longer think of genes as being regulated, nor will anyone refer to normal or proper chromosome functioning.
Talbott points out that the mechanistic models that once seemed so promising in biology have been demolished. The simple line of causation from gene to protein to trait certainly fit Smith’s model of a series of ramps. We know understand that that model is hopelessly simplistic. There are innumerable feedback loops between genes and their products and profound influences on each process exercised by the various systems that make up any organism. Even at the level of a single cell, the operation is vastly complex. Organisms are not machines.
Here is the heart of the matter: The parts of a clock are put together in a certain way; the parts of an organism grow within an integral unity from the very start. They do not add themselves together to form a whole, but rather progressively differentiate themselves out of the prior wholeness of seed or germ. They are growing even as they begin functioning, and their functioning is a contribution toward their growing. The parts never were and never are completely separate, never are assembled. A specific bit of food taken in from outside never becomes some new, recognizable part, added to the rest; rather, it is metabolically transformed and assimilated by the ruling unity that is already there. The structures performing this work, such as they are, are themselves being formed out of the work. Does any of this sound remotely like a machine?
When, on the other hand, we do build machines, we impose our designs upon them from without, articulating the parts together so that by means of their external relations they can perform the functions or achieve the purposes we intended for them. Those same relations give us our explanation of the machine’s physical performance.
He identifies three themes that distinguish organisms from machines. One is the relationship between the parts and the whole. In machines, the functioning of the whole is a simple sum of the action of all the parts. The organism is imposed from outside by the designer. Organisms are different.
The form, existence, and activities of the parts depend upon, and arise from — are in some sense caused by — the whole, which is therefore expressed in one way or another through every part. This is much like the relation between individual words and their context — which is not surprising, since language is itself an expression of organic life.
A machine has no agenda; only the manufacturers and operators have agendas.
Biological activities are carried out as if “with a view toward” or “for the sake of” some end. The organism “aims” to develop and sustain itself as a being with its own particular character.
While a machine may incorporate feedback loops, the operation is still a linear process that proceeds from the actions of the parts. In an organism, the parts are what they are because of the feedback loops.
To give an archetypal example, as the embryo polarizes into anterior and posterior, each pole is not only “opposite” to the other, but necessarily implied in the other. Each pole is properly formed only by virtue of the other’s being formed. Neither is a unilateral cause of the other.
Most interestingly, Talbott argues that the failure to recognize non-mechanistic character of living organisms leads many biologists to attribute mysterious powers to such things as DNA.
To say, as Nobel laureate Max Delbrück once did, that DNA could be conceived in the manner of Aristotle’s First Cause and Unmoved Mover, since it “acts, creates form and development, and is not changed in the process” — well, that’s a stupefying blind spot, a blind spot that to one degree or another dominated the entire era of molecular biology through the turn of the current century. It was already recognized and warned against by the German botanist Fritz Noll in 1903, who pointed out how (in E.S. Russell’s paraphrase) “the chief theorists have tried to solve the problem of development by assuming a material and particulate basis [today’s ‘gene’], without however attempting to explain how the mere presence of material elements could exert a controlling influence on development. They have been forced to ascribe to such abstract material units properties and powers with which they would hesitate to credit the cell as a whole.”
Weiss emphasizes very much the same point: because there is no possible way to make global sense of genes and their myriad companion molecules by remaining at their level, researchers have “simply bestowed upon the gene the faculty of spontaneity, the power of ‘dictating,’ ‘informing,’ ‘regulating,’ ‘controlling,’ etc.” And today, one could add, there is at least an equal emphasis on how other molecules “regulate” and “control” the genes! Clearly something isn’t working in this picture of mechanistic control. And the proof lies in the covert, inconsistent, and perhaps unconscious invocation of higher coordinating powers through the use of these loaded words — words that owe their meaning ultimately to the mind, with its power to understand information, to contextualize it, to regulate on the basis of it, and to act in service of an overall goal.
This strikes me as quite correct. Organisms are Aristotelian wholes. Unlike machines, the organism strives to maintain its being by controlling and incorporating subordinate organisms and cells, each of which is trying to do the same. We have come a long way beyond Aristotle’s biology only to arrive at Aristotle’s biology.