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Feedback Request: Myths of Evolution

This coming Tuesday the Summer of Evolutionary Mythology closes with an interview with evolutionary biologist John O. Reiss that bookends this series of posts. Hope you enjoyed these extracts from Myths of Evolution - I should probably leave it there for now, and concentrate on getting the draft manuscript completed. 

Thoughts on the kind of work I'm doing in this book would be most welcome, even if you're not really familiar with the subject material. Does this kind of critical approach to evolutionary theory interest you? Are these essays too complicated to follow? Did you learn something new from reading them? Please share your thoughts in the comments!

Also: please help me refine my subtitle. I was going to use Scientific Metaphor and the Nature of Life but it's been pointed out to me that "metaphor" is a pretty academic word. I'm now thinking Revealing the Nature of Life is a better subtitle. Thoughts on this also welcome!

Imaginary Evolution (2): Fitness

Last week, the metaphor of “selection” led to questions about what “fitness” is supposed to mean. And now, the conclusion.

Imperata Grass The “confusion about fitness”, as Ariew and Lewontin call it, comes from ignoring a rather obvious problem. Contemporary science is in love with its numbers – empirically-minded people adore the precision of physics – but this infatuation with mathematics isn’t always appropriate. Indeed, British philosopher Mary Midgley observes that our use of the terms “hard science” and “soft science” embed a kind of hierarchical judgment – the more mathematical a science appears to be, the “harder” it is assumed to be, and “hard” beats “soft” much as rock-beats-scissors. But Darwin’s idea of fitness to environment doesn’t lend itself to a simple numeric measure – it’s a complicated, multi-faceted fiction, one that enables us to think differently about the nature of life, but only “softly”. For most kinds of life on our planet, there is no way to make fitness into a neat number, much less one with predictive value – there may be no way at all to talk about one animal being ‘more fit’ than another outside of the fiction the metaphors provide.

Attempts to provide fitness with a robust, mathematical meaning tend to fall prey of an assumed equivalence between reproductive rates and Darwin’s fitness to environment, as if ‘fitness’ was nothing more than a measure of the number of offspring a creature can produce. Ariew and Lewontin savage the assumptions behind this approach, demonstrating that it just won’t do to treat ‘reproductive fitness’ as a substitute for fitness to environment, and this for a number of reasons, including the fact that a great many organisms have overlapping generations, meaning that reproductive rates are not that simple to calculate. When problems such as these have been recognized, alternative solutions have been offered – but the only secure way of mounting the concept involves measuring actual changes in the abundance of particular species, at which point any kind of explanatory or predictive power has been abandoned.

Furthermore, the attempt to use rates of reproduction as a measure of fitness run into insurmountable problems concerning what it means to count individuals at all. If the idea is that an animal which has a thousand offspring is fitter than an animal that has ten offspring (and perhaps even that the former is a hundred times fitter!) we have to be aware that there are many forms of life for which this kind of simplified view doesn’t really make any sense. Many flowers, for instance, have offspring by seeds, but they also grow vegetatively by putting out underground runners that produce new flowers asexually (pictured above). These new flowers are essentially clones of the original plant – should they be counted as new individuals, or not? If they are individuals, what does this mean for trees, which consist of a vast knot of flowering stems woven together into branches and a trunk? If the flowers are all individuals, the tree can’t be counted as one single individual, but must be treated as many different individuals, despite our strong intuitions to the contrary.

The same problem occurs with colonial organisms, such as the coral polyps that make spectacular coastal reefs. Coral polyps sometimes reproduce sexually, but more commonly they reproduce asexually via a process known as ‘budding’. If fitness is to be measured by counts of offspring, is a polyp that produces a hundred sexually-produced polyps to be considered fitter than a polyp that manages to occupy an entire reef through budding? As Ariew and Lewontin put it, “the problem of fitness and relative evolutionary success demands a solution to the problem of defining an individual.” They trace these issues back to the influence of Thomas Malthus on evolutionary theory and conclude that the genetic notion of ‘reproductive fitness’ just doesn’t fit to Darwin’s fitness to environment.

Ariew has pursued the same issue of what fitness is supposed to mean with the philosopher Zachary Ernst, and identifying severe problems with every attempt thus made to mount ‘fitness’ onto a secure mathematical footing. They are all in favor “reconstructing” the concept of fitness “so that it can play its traditional role in evolutionary explanation.” They just do not believe anyone has actually solved this problem, nor indeed are they convinced that it can be solved. The hope is to secure a meaning for ‘fitness’ that will serve as an explanation for why a particular trait succeeds while others fail, and hence why animals with that trait prosper. But they are doubtful that this is possible.

Particularly at task is a widespread account of fitness we can call fitness as propensity or the propensity interpretation. The basic idea is much as we have already seen in reproductive fitness – the fitness of a particular animal is related to its expected number of offspring. To avoid all the pitfalls of this simplistic approach, however, a more advanced solution is needed which takes into account a ‘family’ of propensities, rather than just reproductive rates. Either way, the fitness of any given animal is taken to be a property of the animal itself, that is, of its natural propensities (hence, ‘fitness as propensity’).

For instance, John Beatty and Susan Finsen offer a solution to the fitness problem in terms of a family of propensities that jointly affect population growth. If all the relevant propensities are included correctly in the model, this should presumably allow fitness as propensity to function as intended – relating fitness to number of offspring by correctly modelling population growth as a consequence of multiple factors. The trouble is, under this approach, different propensities will be needed to consider fitness in any given instance, which means in order to meaningfully talk of ‘fitness’ we must already understand all the relevant factors that contribute to the success of particular traits.

Ariew and Ernst contend that “nature is too variegated. Different biological situations call for different algorithms to explain changes in trait frequencies.” They do not see much hope of salvaging a propensity interpretation that has any predictive value. Part of the problem is that the intrinsic properties of individual animals aren’t really enough to understand why particular animals thrive and others fail. For most creatures, the reasons why any given trait becomes more or less common just aren’t causally determined. In the absence of a general model, it is still possible to pursue a historical investigation into the circumstances that lead to a particular species, but any hope that all such histories might be collapsible into explanatory theories of fitness must be set aside.

In fact, ‘fitness’ is applied most successfully in evolutionary theories when Darwin’s fitness to environment is essentially ignored. Genetic models of evolution that use fitness as a mathematical term (denoted by the letter ‘w’) have prospered, treating fitness purely in terms of changes in gene ratios. These population genetic approaches to fitness work very well in terms of their formulation and application to specific problems in the laboratory. They can be made to fit to artificial selection experiments quite easily, since ‘selection’ in the lab has the literal meaning of a decision (one made by the experimental protocol). But at this point, we’re no longer explaining the nature of life in the same terms that Darwin was using.

What could be called genetic fitness in these kinds of theories doesn’t assess how well a trait or a creature fits to their environment at all, and as such these theories don’t provide any explanation for the changes in the relative abundances of real animals or their genes. This presents a rather significant problem that tends to be ignored: if the successful use of ‘selection’ and ‘fitness’ in population genetic models has no role for the causes of selection, we seem to have inadvertently thrown away Darwin’s theory in its entirety. These genetic models are acausal – they don’t deal in causation at all, whereas Darwin’s natural selection was presented precisely as an explanatory cause. As philosophers of biology Alexander Rosenberg and Frederic Bouchard put it: “In jettisoning fitness, acausal approaches seem to have jettisoned natural selection altogether.”

We are left with Sober’s “two faces” of fitness: a mathematical model, gainfully deployed by population geneticists, and the imaginative concept of fitness to environment that originates in Darwin’s theory. But these are not two faces of the same beast – they are entirely different animals, the later dealing with causes, and the former modelling probabilistic reproduction rates with no reference to causes. As Sober notes, “fitness began its career in biology long before evolutionary theory was mathematized” – in the interim, the term has not maintained a constant meaning at all.

Of course, as Sober later notes with biologist David Sloan Wilson, while mathematics has proved important in evolutionary studies “it isn’t true that only mathematics is important, nor is it true that mathematics is always important.” The imaginative aspect of selection and fitness may have little (or even nothing) to do with successful population genetic models, but it is still key to what Darwin’s theory is claimed to say.

If, as nearly everyone involved in studying evolution would attest, differential survivorship in response to diverse environments is an important part of the history of life, then we admit that Darwin’s imaginative imagery of selection, and the fictional account of fitness, are still important, despite having vanished entirely from the hard algebraic accounts of population genetics. Despite the supposed claims of “hard science” over “soft science”, the mythology in this case somehow offers more than the mathematics.

Extracted from the draft manuscript of Myths of Evolution, due from Zero Books in 2012.

Imaginary Evolution (1): Selection

In the first of two posts discussing the role of scientific metaphor in evolutionary theory, we look at what is meant by “selection”.

The trouble with trying to ferret out what Stephen Jay Gould called “canonical imagery” in science, and especially in evolutionary studies, is that science is thoroughly dependent upon metaphor – and even more so when scientists try to explain theories to a wider audience. Gould stated that he knows “no other subject so distorted by canonical icons: the image we see reflects social preferences and psychological hopes,” rather than data or theory.

But this critique doesn’t go far enough, since the theories themselves are equally packed full of metaphors with just as much power to distort thinking if not considered carefully. Gould notes: “If icons are central to our thought, nor peripheral frills, then the issue of alternative representation becomes fundamental to the history of changing ideas in science”. It is this issue of “alternative representation” that we need to address in considering the myths of evolution – because even if we believe that the facts don’t change, the way we present those facts does change, and different metaphors guide thinking in radically different ways.

Two of the central metaphors in contemporary evolutionary theories have been with the field more or less since its inception with Darwin: the metaphors of selection and of fitness. It is almost impossible to have a discussion of the subject without using these words, yet the terms are as much “canonical icons” as the Ladder of Progress (satirically pictured above) that Gould justifiably challenged. ‘Selection’ was only ever a metaphor, and in so much as the ‘fitness’ implied by Darwin’s theory can be rendered meaningful, it must be understood as a useful fiction. There is just as much risk of being misled by the imagery these terms conjure to mind as anything else in science, and yet it seems nearly impossible to excise them from the evolutionary lexicon.

Darwin was acutely aware of the fact that his use of ‘selection’ in Origin of Species was a metaphor. He received letters from Alfred Russel Wallace, the naturalist who was postulating a very similar theory at the same time as Darwin, expressing concern that the term ‘natural selection’ was too anthropomorphic, leading to a personification of nature as “selecting” or “preferring”. Philosopher Michael Ruse notes in this regard:

In his heart, Darwin seems never to have wavered, and he responded to those who criticized the term “selection” by pointing out that it was a metaphor, and who can do science without being metaphorical? “No one objects to chemists speaking of ‘elective affinity,’ and certainly an acid has no more choice in combining with a base, than the conditions of life have in determining whether or not a new form be selected or preserved.”

John F. Haught suggests that Darwin might have been more flexible in this regard, noting that the later Darwin writings sometimes seems to offer “natural preservation” as more suitable than “natural selection”, but whatever Darwin’s feelings the term selection has certainly stuck. Darwin publicly dismissed any problems with the metaphorical aspect of the term on the grounds that science was effectively impossible without metaphorical thinking, but this does not mean Darwin was blind to the kind of constraints on thought that specific images convey. He avoided using the word ‘evolution’ precisely because he didn’t want to take upon the baggage the term had already acquired in terms of conveying a sense of progress and destiny. He seems to have believed, rightly or wrongly, that the term ‘selection’ could sidestep this kind of implication.

In order to fully understand contemporary evolutionary theories, it is necessary to separate – in as much as this is possible – the metaphors from the facts, the myths from the models. A conscientious audit of metaphorical terms like ‘selection’ and ‘fitness’ has much to show us about both evolution and about science in general, but this kind of critique is usually avoided, perhaps for fear of adding fuel to the fire being tended by opponents to evolution. This concern is not warranted. People are perfectly entitled to reject a particular scientific theory for whatever reason they choose, and they are especially free to object to those theories that they suspect have been ideologically contaminated. Frankly, there is little doubt that the presentation of evolution in public has been distorted in this way, and this by people on both sides of the fence. A defence of evolutionary studies should rest on an honest understanding of the issues, and this necessitates an acceptance of the role of imagination in its operation.

When I call ‘selection’ imaginary, or suggest that ‘fitness’ is a fiction, I do not mean that all evolutionary theories are mere figments, but rather that these terms cannot be understood without reference to imagination. Metaphor is an imaginative activity – the process of thinking about one thing by comparison to another. Science, as Darwin recognized, thrives on this kind of analogical thinking, because science – in common with the arts – is fundamentally an imaginative activity. True, much of a research scientist’s time is absorbed in experiments, observation and data, none of which is enormously creative. But the experiments being conducted, and even more so the concepts that motivate those experiments, all began life as imaginative fictions. Every theory inevitably implies a story.

The fiction in which the term selection gets its meaning is that whereby it is as if something has made a decision that selects some animals and not others to survive (for natural selection) or to reproduce (for sexual selection). Because selection is intended as a scientific metaphor, it is generally considered poor form to indulge in speculations as to the obvious consequences of the fiction e.g. if we say that Mother Nature does the selecting, we’ve brought in a mythic figure (‘Mother Nature’) into what was supposed to be a sober, scientific term. This was precisely Wallace’s objection to Darwin’s use of ‘selection’ – these kinds of extrapolations follow all too easily. Darwin’s counter was that it is useful to think in terms of selection, the story does some valuable work for us in terms of focusing our attention onto what is happening.

This brings us to the other important part of Darwin’s fictional representation of how creatures change over time: fitness. Darwin didn’t actually use the term, but did make reference to individual animals being “fitter” or being more or less “fit” than others; it is from this informal discussion of a comparative scale of “fitter” animals that the modern concept of fitness develops. Philosopher André Ariew and geneticist Richard Lewontin are very clear on the role of metaphor in this part of Darwin’s ideas:

Different individual members of a species, then, ‘fit’ into the environment to different degrees as a consequence of their variant natural properties, and those that made the best ‘fit’ would survive and reproduce their kind better than those whose ‘fit’ was poorer. The word ‘fit’ (‘fittest’, ‘fitness’) is a metaphorical extension of its everyday English meaning as the degree to which an object (the organism) matches a pattern that is pre-existent and independently determined (the environment). This metaphorical lock-and-key fitting of the organism into the environment is reflected in the modern concept in ecology of the environmental or ecological ‘niche’ that species are said to ‘occupy’.

We can see here the fiction that Darwin was using in his original conception in Origin of Species: some animals ‘fit’ better into their environment, and these are ‘selected’ to survive. It is as if the world is a partially completed jigsaw, with a certain number of gaps for extra pieces. Those pieces that fit into the jigsaw persist, while those that don’t fit are discarded. The heuristic value of thinking this way is comparatively clear, and the benefits can be conveyed irrespective of whatever imaginative gloss we add to the core metaphor – the jigsaw image I just proposed, for instance, or Ariew and Lewontin’s lock-and-key image.

However, in the decades since Darwin, the term fitness has expanded to take onto its metaphorical shoulders far more than Darwin ever intended. In the words of philosopher of biology, Elliott Sober, fitness has “two faces”. It not only describes the relationship between an animal and its environment, as described above, but leads a double life as a mathematical term used in formulating predictions. In Sober’s words: “Fitness is both an ecological descriptor and a mathematical predictor.” Trouble is, this double life threatens to wear fitness rather thin; the strain of pretending that the mathematical face is still a fit to Darwin’s original use might just be too much for it to bear.

Extracted from the draft manuscript of Myths of Evolution, due from Zero Books in 2012.

Next week: Fitness

Videogame Cultures 3/Fighting Used Game Sales

Skip over to ihobo for my thoughts on the conference I just finished:

Where does the games as art debate go now? How much do stereotypes of the gamer dominate and distort perspectives of games in culture? Can counterplay and co-creation in games change the relationship between the makers and players of games? Issues such as these were the focus of lively debate in-and-out of the conference halls at Videogame Cultures 3 in Oxford University’s Mansfield College.

Read the whole thing in Highlights of Videogame Cultures 3.

Also over on, a short rant about how Fighting Used Game Sales is Suicide. This is an old topic of mine, but I think I mostly wrote about it before I started blogging.

The Borders of Science

Razor wire Where exactly will we find the boundaries of science that the ignorant hordes of religion are accused of invading?

This mythic image of a ‘war’ between science and religion has become so commonplace that it has become very easy to buy into it, especially in the context of evolution, which serves as the frontline of the alleged battle. This story does not, however, bear up under scrutiny. This does not mean that there isn’t a conflict – it’s abundantly clear that there is a political fight going on in the United States over the education system, for instance, and echoes of the same can be found in the Islamic world. But as Charles Taylor notes, the idealised view of “religion” versus “science” is an ideological construct that masks an intellectual struggle with complex agendas.

For a war between “science” and “religion” to be viable, there must be some common territory. If not, there can be wars within “science”, just as there are certainly conflicts within “religion”, but there cannot be a dispute between them. The question has to be: is there common ground between the two, and if there is, does it lie beyond Popper’s milestone, out in the vast untestable tracts of metaphysics? Because if this is the only place “science” and “religion” intersect, we had better learn to live with the problem, because we shall certainly never resolve metaphysical disputes to anyone’s satisfaction.

Let us drop the scare quotes for now and pretend that we know what the terms science and religion mean, at least in broad strokes. To some extent, this condemns ‘religion’ to end up meaning ‘Christianity or other religions that are similar to Christianity such as Islam’, which I feel is gross misunderstanding of the beliefs of the people on our planet, but alas this cannot be helped. It certainly seems that many of the vocal critics of religion focus their ire on Christians and just assume that all other religions are essentially the same under the hood, but as it happens many of the people who have actively explored the relationship between science and religion have made an explicit choice to treat ‘religion’ as meaning ‘faith tradition’ or ‘Christianity’, if only for practical reasons.

One such intrepid explorer – indeed, the person credited with founding ‘Science and Religion’ as an area of study – is Ian Barbour. In 1990, he proposed a fourfold typology as a means of sorting out the various ways people have related science and religion; although he has made some minor revisions, he had continued to use this system ever since. It is widely taught as a means of examining the issues in the interface between science and religion. The four boxes in his model are as follows.

Firstly, conflict, in which science and religion are seen as enemies. Barbour makes the point that both Creationists and atheistic scientists agree on this point, seeing it as impossible for a person to believe in both God and evolution. They only disagree about which to accept. Barbour notes that these two groups “get most attention from the media, since a conflict makes a more exciting new story than the distinctions made by persons between these two extremes who accept both evolution and some form of theism.” Richard Dawkins is a prominent example of someone espousing conflict.

Secondly, independence, in which science and religion are seen as strangers that can get along “as long as they keep a safe distance from each other”. This viewpoint denies the validity of any claimed conflict, since science and religion are claimed to refer to differing domains of life. This perspective corresponds to geneticist Theodosius Dobzhansky’s remark that “science and religion deal with different aspects of existence. If one dares to overschematize for the sake of clarity, one may say that these are the aspect of fact and the aspect of meaning.” Barbour notes that separating the two fields into “separate watertight compartments” is a way to avoid conflict “but at the price of preventing constructive interaction.” Stephen Jay Gould was a prominent example of someone espousing independence.

Thirdly, dialogue, in which both similarities and differences are acknowledged, and conversation is facilitated between (say) theologians and scientists. Barbour suggests that dialogue can occur at the limits of science, when it faces a question that it cannot answer such as “Why is the universe orderly and intelligible?” It can also occur when ideas from science are used to influence theological interpretations of the relationship of God to the world. Unlike independence, dialogue doesn’t treat science and religion as forever cut off from one another, and unlike conflict, dialogue doesn’t recognise a fundamental incompatibility between the practice of science and religious faith. Barbour himself is an example of this approach.

Lastly, integration, which is a “more systematic and extensive kind of partnership between science and religion”, one that either argues for the reformulation of certain religious beliefs in the light of scientific discoveries (a theology of nature, rather than natural theology), or that tries to interpret scientific and religious thought within a common framework (such as process theology). Pierre Teilhard de Chardin is sometimes given as an example of this approach, although Barbour admits to supporting integration as well as dialogue.

Another similar typology has been offered by Catholic theologian John F. Haught, one in which the four categories are whimsically given titles beginning with the same letter: conflict, contrast, contact and confirmation. Barbour recognises that the first two categories are the same in both systems (i.e. Haught’s ‘contrast’ is the same as Barbour’s ‘independence’), and suggests that Haught’s term ‘contact’ combines the themes of Barbour’s ‘dialogue’ and ‘integration’ into one heading – indeed, Barbour notes that “there is no sharp line” separating dialogue from integration, so Haught’s conflation in this regard is not unreasoanble. The final category, ‘confirmation’, refers to the validation of scientific thought by background assumptions that originated in theology (such as belief in the rationality and intelligibility of the world), and Barbour suggests that this is for him can be considered a form of dialogue.

What can be gained from Barbour’s discussions of Haught’s closely related typology is that the idea of four categories doesn’t quite stack up in either of the two models on offer. According to Barbour, ‘integration’ is not sharply delineated from ‘dialogue’, and Haught’s ‘confirmation’ also a form of dialogue – suggesting that both approaches collapse into just three categories – conflict, independence and dialogue (or conflict, contrast and contact). However, some further conceptual analysis may shed some light onto what it is exactly that either system is supposed to be reflecting.

The essence of the conflict position – whether espoused by a diehard atheist like Dawkins, or the Creationists he despises – is an absolute and objectivist attitude towards truth. There is one account of what is true, and hence once you are sure you have the correct account of the truth you can safely dismiss all other accounts as being in error. This can be contrasted against the independence and dialogue positions, both of which take a perspectival attitude towards truth. This is not to claim that the truth is inescapably relative or unobtainable, but rather to suggest that different perspectives can offer an important part of the true picture and, further, that absolute and objective truth cannot be achieved directly (except, for theists, by God). For independence, the truth is perspectival because science and religion make different claims; for dialogue, the truth is perspectival because science and religion approach the world from different (but potentially complementary) angles.

If independence and dialogue have this perspectival attitude towards truth in common, what distinguishes them? It is their differing attitude towards the domains or languages of science and religion. Independence entails disjunction, as both Barbour and Haught assert. On this account, science and religion are different fields, they use different languages, and they talk about different things, as in Gould’s proposal of “Non-Overlapping Magisteria” (NOMA) whereby science is characterised as “our drive to understand the factual character of nature” and religion is characterised as “our need to define meaning in our lives and a moral basis for our actions”  – just as in Dobzhansky’s simplification of science and religion into aspects of “fact” and “meaning”.

Conversely, dialogue (and, by extension Barbour’s integration and Haught’s confirmation) entails intersection between science and religion; rather than treating the two as if they are partitioned into “watertight compartments”, they are allowed to interrelate. While a non-religious individual such as Gould can be content with carving up distinct territories for science and religion, people of faith such as both Barbour and Haught are generally less comfortable with this solution. This is a point H. Allen Orr astutely makes in his review of Gould’s NOMA proposal: “If your religion is dictated by science, the two are non-overlapping. But if your religion is independent of science, the two routinely tread on each other’s toes.” Indeed, Barbour makes it clear why he believes dialogue is preferable to independence:

We cannot remain content with science and religion as unrelated languages if they are languages about the same world. If we seek a coherent interpretation of all experience, we cannot avoid the search for a more unified worldview.

In other words, the attempt to compartmentalise science and religion has the undesired effect for many religiously minded people of demoting religion with respect to science – fact somehow outranks meaning, in so much as one wants to believe that both are talking about the same world. There is something of an echo of the desire for absolute truth that epitomizes the conflict positions in this approach: if religion has nothing to do with fact, doesn’t this come close to saying that religion isn’t true at all?

This conceptual analysis has an additional consequence: the distinction between disjunction and intersection can also be applied to the conflict camp. As Barbour and Haught have it, Creationists and their atheist opponents all fall into one box. This is a convenient grouping in so much as it shows up what Taylor calls the “strangely intra-mural quality” of the alleged war between science and religion, and certainly in so much as the atheist faction is conducting their own brand of theology (admittedly, atheology) the disagreements do have some common ground here. But at the same time, there is something deeply distinctive about what Creation Science or Intelligent Design proposes, in that it rests on a presumed intersection between science and religion – both must conform to a common truth – whereas naturalistic atheism rests on a disjunction – science is true, therefore religion is false.

If my conceptual analysis is accepted, then we are back to four categories in the relationship between religion and science – but they are not quite the same as those proposed by Barbour and Haught. There are two positions based on belief in absolute truth, the absolute disjunction of ‘conflict atheism’ and the absolute intersection of ‘conflict theism’. There are also two positions based on belief in indirect access to truth, the perspectival disjunction of Gould’s NOMA and its equivalents and the perspectival intersection of theology of nature and other forms of dialogue. But as Orr suggests, Gould’s position begins outside of religion, whereas Barbour, Haught and other advocates of dialogue begin in positions that begin inside of religion.

In this respect, you might expect an advocate of independence, like Gould, to have some sympathy for conflict atheism – but of course, Gould and Dawkins were bitter rivals (admittedly, mostly over scientific issues). Similarly, you might expect an advocate of dialogue to have some sympathy for conflict theism, since they share in common a relationship with religion. But the opposite is true – Barbour says that “creation science is a threat to both religious and scientific freedom”, while Haught calls it “a scandal” that there are Christians who accept a literal interpretation of the Garden of Eden and “deplorable that there are still so many defenders of ID and creationism”. It seems that whichever camp you fall into, everyone else has it wrong.

So who’s right and who’s wrong? I’m going to take the least popular position and suggest that all four of these camps have an important piece of the puzzle. Both the perspectival positions have it right that absolute truth isn’t something we have access to as mere humans, but advocates of disjunction have to massively simplify what religion is allowed to mean in order to make their plan work, and this just isn’t acceptable to most people of faith. Conversely, in condemning their more literally-minded cousins, advocates of dialogue are trying to buy respectability for their theology at the risk of denying freedom of belief to those believers unable to make peace with evolution. But the reason these people are denying evolution has very little to do with science, and everything to do with the conflict atheists’ clumsy attempts at theology. Thus both the absolute camps are correctly calling on the faults of their vocal opponents, even though their own positions rest on sand.

Ultimately, if we take seriously the commitment to freedom of belief at the heart of contemporary conceptions of Human Rights, the challenge shouldn’t be to establish who is right and who is wrong – as ever was the case, everyone is right in some sense, and everyone is wrong in another sense. The challenge shouldn’t be to settle the argument – in so much as key parts of the dispute are far beyond Popper’s milestone (e.g. resolving existence claims for God), this simply isn’t an option. What we have to find is not the right answer, but a workable solution that allows everyone concerned to live together.

Extracted from the draft manuscript of Myths of Evolution, due from Zero Books in 2012.

Imaginary Games Out Now?

The Zer0 Books website lists Imaginary Games with a “Buy Now” button, so despite the release date in November there may already by copies in stock in the warehouse. (Zer0 did mention to me that unlike other publishers, they make books available as soon as they’re in stock, rather than holding them back for the release date).

Perhaps someone who was planning to buy a paper copy of the book could make an order and let me know if it turns up?

Why Co-operation? (2) Group Selection Strikes Back

Last week, the rise of kin selection as an explanation for co-operative behaviour, and the dismissal of group selection as significant. And now, the conclusion…

Williams George C. Williams, an evolutionary biologist specializing in fish (pictured here with his always awesome beard), was a particularly influential voice in the case mounted against group selection. His 1966 book Adaptation and Natural Selection laid out the basis for the gene centred view of evolution (and was, in fact, a major source of the ideas Dawkins presented in The Selfish Gene ten years later). Williams examined a variety of possible cases of group selection (mostly in fish species) and determined in each than an explanation in terms of individual selection was always available. He thus concluded that selection between groups was “impotent in a world dominated by genic selection and random evolutionary processes”. He did not dismiss the possibility of group selection completely, but asserted that biologists should “postulate adaptation at no higher a level than is necessitated by the facts.” Williams was mindful of the inherently changeable world of scientific models, however, admitting that there was still much to be learned: “I am sure that by the standards of a generation hence, our current picture of evolutionary adaptation is, at best, oversimplified and naïve.”

Sober and Wilson recently returned to Williams’ seminal text in order to reassess the relative merits of the kin selection and group selection perspectives. Praising much of the foundational work Williams pursued, they draw particular attention to the idea that “adaptation at a level requires selection at that level”, calling this Williams’ principle. This adage sets the requirement that must be met for group selection to be considered valid: the fact that some trait provides a recognizable benefit to groups isn’t enough for that trait to be considered a group adaptation – it must have developed precisely because it was beneficial to the group. Using this as the basis for their discussions, they criticize a number of biologists for violating Williams’ principle, and thus continuing to defend a kin selection-inspired perspective against group selection.

The biologists in question are typical examples of the exaltation of genes this chapter addresses, maintaining (Sober and Wilson assert) “that the individual is always a unit of adaptation no matter what the mix is of group and individual selection.” Sober and Wilson point out that this position is being held on the basis that individuals are predicted to maximize their inclusive fitness, and this claim holds true irrespective of the relative strengths of individual or group selection. But this violates Williams’ principle. Kin selection arguments can’t rule out group selection from happening, since inclusive fitness only entails claims about the rates of gene survival – it has nothing whatsoever to say about the scale at which adaptations occur. In fact, as philosopher of science Samir Okasha has noted, rather than claiming individual selection always occurs, there are many situations in which the question of whether or not there is individual selection taking place is not defined.

There are now a vanguard of scientists and philosophers who recognize that it is not the case that group selection is a force too weak to have any influence in evolution, and champion what is called multi-level selection – the idea that selection and adaptation can occur at the level of the individual, the group, or even at the level of an ecology. Note, however, that in all these cases, the accumulation of changes still happens via alterations in gene frequencies (although it is important to remember that even among animals there are also persistent cultural and environmental effects that play an important role in the story of life). The breakthrough realization has been that the metaphorical ‘selection’ that takes place occurs within a specific context. It is always possible to render these effects solely in individualistic terms, but transformable perspectives are not always equivalent in explanatory value. If group selection played a major role in the occurrence of a particular trait, is it really helpful to talk about that trait as an individual adaptation?

This is not just, as Dawkins has accused, merely “semantic doubletalk”. Empirical results validate the multi-level selection perspective, and show how focusing solely on genes can only give an incomplete perspective on evolution. For instance, William Muir has demonstrated that artificial group selection of hens results in decreased mortality of the birds, and increased egg production, with the bulk of the improvement occurring within just three generations. As another example, William Swenson, David Sloan Wilson and Robert Elias showed that artificial group selection of microbial ecosystems in soils lead to improved growth for plants grown in that soil. Far from group selection being too weak a force to have any serious influence, it seems it is strong enough to have dramatic and demonstrable effects.

However, if Kuhn taught us anything about the history of science it is that research communities do not change their beliefs without a fight – often, you might say, to the death. Hamilton, however, who did much of the heavy lifting on kin selection and had been originally opposed to the viability of group selection, changed his view almost completely as a result of a fascinating equation by George R. Price that, alas, is slightly too complex to explain here. As Wilson, notes, Hamilton was happy to change his mind once he recognized that “inclusive fitness theory is not an alternative to group selection after all; the role of group selection was merely obscured by the way it was formulated.”

What really put the cat among the pigeons in recent years was a paper by Martin Nowak, Corina Tarnita and Edward O. Wilson that denies the validity of using kin selection to explain the origins of the behaviour of social insects such as ants. Edward O. Wilson is particularly famous in evolutionary circles as the founder of sociobiology, not to mention an expert on insect species of all kinds, and his apparent change of heart in respect to the validity of group selection raised both eyebrows and tempers. In fact, he has been moving in this direction for some time, and published several earlier papers dealing with the topic, all stating the same thing: kin selection wasn’t a significant factor in the evolution of ant social behaviour, while selection between colonies (i.e. multi-level selection at the level of the colony) appears to have played a highly significant role.

Ants and wasps had generally been considered a great example of the merits of the inclusive fitness perspective advanced in kin selection, owing to a rather unique system of inheritance. Whereas most animals pass on half of their genes to their offspring (hence children share half their genes with each of their parents), many social insect species have females with genes from both parents and males with genes only from the mother (the queen). Since the queen passes on all the genes to the males, this means that whichever male the queen mates with, her daughters will have three quarters of their genes in common with their mother queen. In terms of Haldane’s jest, this means that four ant sisters will sacrifice themselves for three queens – a pretty good rate of exchange! These numbers were sometimes claimed to be a validation of inclusive fitness, serving to explain why ants and bees had such tight social structures.

Trouble is, this explanation never actually stacked up in practice. For a start, remember that the formula for kin selection, Hamilton’s rule, is only a description of optimal conditions – it isn’t actually an explanatory mechanism. As Christopher Jensen has noted, it’s rather remarkable that no-one has incorporated Hamilton’s ideas into a predictive scientific model that demonstrates how these insect species reach the optimal state predicted. In the absence of such a model, as Nowak and colleagues suggest, the high relatedness might be better understood as a consequence of the highly social living arrangements, not as a cause.

What’s more, as Raghavendra Gadagkar reports, the actual level of relatedness in insect colonies is considerably lower than the ideal values suggest, not to mention there are a wide variety of social insects that don’t have the unusual inheritance pattern described above. Gadagkar suggests that an exclusive focus on relatedness isn’t good enough for proving Hamilton’s rule; the benefits and costs have to be measured in some way, not simply brushed under the carpet. His own research group has attempted to find ways to attend to this deficit, and when they have done so they have concluded that “ecological, demographic and physiological factors” have a bigger role in bringing about the unique social arrangements of communal insects.

Both Jensen and Gadagkar, commenting on the controversial Nowack, Tarnita, and Wilson paper, reach similar conclusions: kin selection and group selection aren’t really in competition with each other, they are simply different tools that need to be applied in different ways. Jensen notes in particular that there are situations in which Hamilton’s rule can be useful – it just shouldn’t be taken as the default explanation. Furthermore, even if group selection is a better explanatory device in respect of social insects, “we need to acknowledge that different theoretical constructs will be useful to explain different evolutionary phenomena.”

Regarding the intensity of the backlash against the paper, Jensen recognises that there are evolutionists who are “wholly committed to the idea of gene-level selection” and who “insist that all arguments rest on the tenet that the gene is the sole unit of selection”. He comments that the paper has thus “exposed some very disturbing things about the sociology of evolutionary biology”:

This publication has really angered a great number of people, and this anger has revealed the kind of tribal orthodoxy that exists in the mainstream of evolutionary biology. A great number of evolutionary biologists will become enraged whenever someone in the field espouses a hypothesis that contradicts the gene-centred approach to explaining evolutionary processes... the anger often seems excessive in relation to the affront. After all, if an idea is clearly dumb and can easily be dispatched by theoretical or empirical demonstration, why get upset about it? We need more publication of relevant results, not more rhetoric.

It is worth reiterating that the gene’s eye view is a perfectly workable scientific metaphor. It only creates problems when it develops into a monomaniacal fixation with genes. Yes, genes are absolutely crucial to understanding the evolution of life, because without changes in the abundance of different gene variants much of what we consider natural selection simply has too little to work with. But when it comes to the evolution of co-operation, the kin selection perspective has radically less to offer than multi-level selection theory.

Co-operation allows groups of animals – even unrelated animals – to gain a significant edge over rival groups that don’t co-operate, or who co-operate less well. This situation can lead to the evolution of group adaptations for co-operation, as appears to have happened with social insects. And of course, even without group selection for collaboration, co-operation can still be the best strategy. Rather than the myth that co-operation is constrained to occur only between relatives, we need a new myth that expresses the inherent advantages of working together.

Extracted from the draft manuscript of Myths of Evolution, due from Zero Books in 2012.