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Saturday, July 13, 2019

Reactionary fringe meets mutation-biased adaptation.
5. Beyond the "Synthesis" debate

This is the sixth in a series of guest posts by Arlin Stoltzfus on the role of mutation as a dispositional factor in evolution.

Reactionary fringe meets mutation-biased adaptation. 5. Beyond the "Synthesis" debate
by Arlin Stoltzfus

The authors of TREE's hatchet piece imply that the theory of Yampolsky and Stoltzfus (2001) is somehow not new, citing ancient work from Dobzhansky and Haldane. In Box 1, they argue that this theory is part of "standard evolutionary theory," showing a 4-step derivation ending in Eqn IV, which is Eqn 2 of Yampolsky and Stoltzfus (2001), and informing the reader that this is based on "classical" results from Fisher, Haldane and Kimura, who are named, while Yampolsky and Stoltzfus are not named.

Yet, Fisher, Haldane, and Kimura did not make the argument in Box 1, did not follow the 4 steps, and did not derive Eqn IV!

Reactionary fringe meets mutation-biased adaptation
1. The empirical case
2. Some objections addressed
3. The causes and consequences of biases in the introduction process
4. What makes this new?
5. Beyond the "Synthesis" debate
    -Thinking about theories
    -Modern Synthesis of 1959
    -How history is distorted
6. What "limits" adaptation?
Indeed, we discovered last time that Haldane and Fisher, who died before origin-fixation models emerged in 1969 (McCandlish and Stoltzfus, 2014), argued against the potential for mutation-induced evolutionary tendencies, and their argument was repeated for another 70 years.

What is the purpose of this deception? Why would the authors divert credit for new theoretical findings to dead people? Why would TREE give a platform to authors who violate norms of scholarly attribution and exhibit hostility toward a line of research they do not understand?

Welcome to the culture war

The context for this perverse treatment is the convoluted debate over the status of the neo-Darwinian "Modern Synthesis" of the mid-20th century.

This debate, which began in the 1980s, has heated up recently, as reformers have begun to organize, not just via the vapid Third Way, but more credibly via the coalition calling for an "Extended Evolutionary Synthesis" (EES). The EES Front receives funding from the Templeton foundation, which causes concern to many scientists, and sends Jerry Coyne into paroxysms of indignation. Traditionalists were inflamed in 2016 when the Royal Society hosted a reform-themed conference organized by reformers and outsiders.1 The tone of the traditionalists, their authority seriously challenged, has become strident and desperate.

It was in this context that the reactionary authors of TREE's hatchet piece identified my colleagues and I as part of the barbarian horde of "critics of standard evolutionary theory" ready to breach the citadel of Synthesis orthodoxy.

Why do I call this a culture war? Why not frame this as an empirically resolvable dispute between two theories, Standard Evolutionary Theory (SET) and the Extended Evolutionary Synthesis (EES)?

Let us consider this question. The reformers hold that the gene-centric view of SET
"fails to capture the full gamut of processes that direct evolution. Missing pieces include how physical development influences the generation of variation (developmental bias); how the environment directly shapes organisms' traits (plasticity); how organisms modify environments (niche construction); and how organisms transmit more than genes across generations (extra-genetic inheritance). For SET, these phenomena are just outcomes of evolution. For the EES, they are also causes." (From "Does evolutionary theory need a rethink.")
That is, SET and EES are characterized with sets of "processes that direct evolution."  To offer an "extended" version of SET is to extend its list.

This does not mean that SET and EES are testable theories: they might be flexible research programs or schools of thought that shift emphasis and welcome new ideas, so that each one could evolve into the other.

Of course, the distinctiveness of EES could be translated into falsifiable claims: if SET's list of causes is incomplete, as the EES Front claims, then an account of evolution based on SET would be empirically insufficient.

For instance, EES includes developmental biases among the "processes that direct evolution." By contrast, according to the dichotomy of roles essential to neo-Darwinism, variation merely supplies raw materials, whereas selection is the governing force providing initiative, creativity, and direction-- a distinction reflected in Mayr's statement (figure), or the quotation about the essence of neo-Darwinism from Gould (1977) that appears in the left side-bar of SandWalk (see also Gould 2002, pp. 137 to 146).

Thus, if some of the directionality of evolution is due to developmental bias, whereas the neo-Darwinian position is that all of it is due to selection, then SET fails.

Likewise, modifications to the environment via niche construction are quantifiable, and so are their feedback effects on evolution, e.g., there is some total non-living mass of constructed environments (anthills, beaver dams, coral reefs, etc) and this must have some quantifiable effects on evolution via increased biomass or species richness. A falsifiable EES theory could predict some evolutionary consequences of increased species richness due to niche construction, and if these consequences can be shown, SET fails.

Yet, we face a challenge with applying such a test: SET defenders have retreated from neo-Darwinism, and they do not agree to a falsifiable position excluding developmental biases or niche construction.

For instance, the 2014 EES-SET debate in Nature (Does evolutionary theory need a rethink?) never invokes neo-Darwinism, though Charles Darwin gets 14 mentions. The participants did not seem to disagree on scientific issues (see The Great Non-Debate on Evolutionary Theory). Wray, et al. (2014), defending SET, acknowledge the in-principle legitimacy of every ostensibly non-traditional EES mode of evolution, which they characterize as "new words, old concepts." They claim that SET is always being extended and revised, and that it already includes all valid ideas of EES, though they raise doubts about the importance of these ideas.

This flexibility is what makes the Synthesis so durable, as historian David Hull (2002) explains in the Oxford Encyclopedia of Evolution: 
"Any criticism of the synthetic theory that turned out to have some substance was subsumed in a modified version of this theory.  Instead of being a weakness, this ability to change is one of the chief strengths of the synthetic theory of evolution.  As in the case of species, scientific theories evolve" Hull (2002) History of Evolutionary Thought
What Hull is describing, of course, is not a genuine scientific theory, but something like a tradition or a school of thought-- the Synthesis-inspired Evolutionary Tradition (SET).

Provine, who wrote the seminal history of the theoretical foundations of the Modern Synthesis, said that it "came unraveled for me during the period since 1980," citing widespread neutral evolution, the abandoned concept of genetic homeostasis, the lack of a unified theory covering molecules and morphology, and the collapse of the "gene pool" view (see Provine's afterword to the 2001 re-printing of The Origins of Theoretical Population Genetics). The original Modern Synthesis held that the "gene pool" acts as a dynamic buffer of diversity that prevents any direct dependence of the rate of evolution on the rate of mutation-- a theory that no one accepts today (see The shift to mutationism is documented in our language). The original Modern Synthesis is a special case, not the foundation of contemporary thinking.

Indeed, traditionalists no longer defend the original theory, but defend a notional "Synthesis" partly by relying on cultural arguments (see Stoltzfus, 2017), e.g., Svensson (2018) argues that reciprocal causation (associated with niche construction) is part of SET because Lewontin, a person associated with the Synthesis tradition, wrote an essay about reciprocal causation, 2 decades after the architects of the Modern Synthesis declared victory without invoking reciprocal causation to account for any important features of evolution.

What about the EES? The architects of the EES understood a decade ago that the notional "Synthesis" was no longer a falsifiable theory, but more like a research program with "a hard core of theories immune to revision, surrounded by a protective belt of malleable theories." The hard core, they assumed, was selectionism and a reductionist focus on upward causation from genes and population genetics. So, they framed EES as an alternative to this bottom-up, gene-centric, selectionist approach, focusing on key causal concepts that emphasize organisms, development, non-genic inheritance and interactions.

That was a strategic mistake. The EES Front under-estimated the flexibility of SET and its apologists, who have already claimed all of the EES extensions. Wray, et al (2014) claim niche construction on the grounds that Darwin worked on earthworms, whereas Futuyma (2017) simply declares the idea to be obvious-- he always knew it but didn't bother to write it up--, which apparently means that Futuyma owns niche construction and can assign it to SET, given his special power to re-write the Synthesis every few years to keep it current.

The treatment of Fisher in TREE's hatchet piece again reveals SET as a flexible tradition, not a scientific theory. In his opening chapter, Fisher (1930) invokes the opposing-pressures argument, repeatedly arguing against any role for mutational tendencies in evolution, and concluding that the researcher who understands how genetics leads inevitably to neo-Darwinism
... will direct his inquiries confidently toward a study of the selective agencies at work throughout the life history of the group in their native habitats, rather than to speculations on the possible causes which influence their mutations.
To accept mutation-biased adaptation is to revoke Fisher's theory.

However, traditions are more flexible than theories. SET defenders do not have to follow Fisher's position, but only to honor the forms of tradition, which they may do in various ways, e.g., by focusing on authority figures, or by simply re-telling the Synthesis story to accommodate new findings. For instance, the way to appropriate a theory of internal biases rejected by Fisher, Haldane, Wright, Simpson, Stebbins, Mayr, Ford, and so on, is to (1) discard the logic and purpose of the theory, breaking it down into parts, and (2) link some of those parts with tradition. This cultural activity cannot be distinguished from science if we have no standards for what constitutes a valid argument about scientific theories. For instance, if scientists do not have a clear understanding that scientific theories are not merely lists of parts, they will be susceptible to this kind of bad argument.

The other third way

By way of disclosure, I am not a member of any reform movement. My primary criticism of the Modern Synthesis is the same as that of Nei, which is that the shifting-gene-frequencies theory gets population genetics wrong. The EES Front invited me to a workshop in 2017, which I enjoyed. In a concluding session, I argued-- extending informal comments and The Great Non-Debate on Evolutionary Theory-- that EES is not a cohesive theory but a list of reforms, and that confronting the notional Synthesis without changing the terms of debate inevitably turns the EES challenge into a cultural battle, a strategy that is not scientific, and that is sure to lose.

In response, one of the standard-bearers of the EES Front said something along the lines of "yes we are waging a culture war, and we will win!"

This comment split the room: half cheered, and the other half were stunned, an incident that prompted me to write Why we don't want another 'Synthesis'. The aims of science would not be served by setting up another intellectual monoculture so deeply attached to a totalizing modernist narrative that, merely to maintain the narrative, it will torture history, distort basic concepts, and sacrifice scientific accountability. When the authors of TREE's hatchet piece claimed evolutionary biases due to internal biases in variation, i.e., orthogenesis, on behalf of the Synthesis, this was merely the latest in a series of increasingly flagrant attempts to shift the goalposts to forestall valid criticisms of historically important ways of thinking.

The next sub-series of posts provides a basis for moving beyond the futile Synthesis debate, by taking a rigorous approach to history, maintaining a firm grasp of what theories mean and how to recognize them, and confronting rhetorical tactics that blur together scientific and cultural arguments.

5.1. Thinking about theories. Here we (1) distinguish theoryC (concrete, conjectural), a grand conjecture or major hypothesis, and theoryA (abstract, analytical), a body of abstract principles; (2) separate theories from spin; and (3) consider the relationships of persons to theories. 

5.2. The Modern Synthesis of 1959. This post describes and documents a cohesive theory of evolutionary genetics that has been quietly abandoned, though it still remains cryptically influential.

5.3. The abuse of history.This post explores (1) Synthesis Historiography, a set of myths about alternative theories and historical developments fabricated mainly by Mayr, and (2) the unconscious introduction of distortions by normality drift and back-projection

5.4. Synthesis apologetics. Synthesis apologetics is not a coherent scientific position, but set of rhetorical tactics. One tactic is to craft a broad description of the Synthesis that is historically correct in what it includes, but deceptive in what it leaves out.

1. Kevin Laland's new view of evolution; The Extended Evolutionary Synthesis - papers from the Royal Society meeting

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