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Tautology 3: The problem spreads

This post will look at two different aspects of the tautology problem:

1. The public aspect, as it becomes a widely used counterargument to “Darwinism”, and the rebuttals of some public “Darwinists”; and

2. How it played out in the biological and philosophical literature.

In 1971, Norman Macbeth, a lawyer, published a critique of Darwinism in a quasilegal argument, Darwin Retried (1971). In it, he laid out the tautology argument with a lawyer’s skill, expressing surprise that a mathematician would recognise it’s tautological nature and not think it was a problem (thereby demonstrating that the law does not understand the role of mathematical expressions in science). This was immensely popular, and was taken as a serious challenge to the “Darwinian consensus” by enough serious scholars that it did not get treated as solely a creationist inspiration, although it certainly was that as well (it is cited by nearly every creationist attack on evolution).

Macbeth inspired Tom Bethell, an economics journalist, to write “Darwin’s Mistake” in the popular Harper’s magazine (Bethell 1976), which repeated Macbeth’s presentation. Stephen Jay Gould, in his monthly column in the AMNH’s Natural History magazine rebutted Bethell’s version [‘ware typos!], and this was eventually published in Gould’s book the next year (Gould 1977). Gould’s response was, effectively that the environment acts in an analogous manner to breeders, ensuring that superior phenotypes will increase, just as Darwin said. Fitness is independent of the definition.

This is how it got into the popular imagination, and thus into various creationist websites and books. Darwinism is false because, errr, well it’s not entirely clear how a principle that, if a tautology, is always true can show that the theory it resides in is false, but then we never expected creationists to be coherent on this. Why, though, do philosophers and biologists take it so seriously? Because they do. Or rather they did. Few books recently treat it as a live issue (two exceptions being Grene and Depew 2004:262f, and Garvey 2007: 160-167).

But some biologists took this seriously: I have already mentioned Waddington. Then there is a review by Donn Rosen, a fish taxonomist (1978), which basically said that the tautology problem undercut neo-Darwinism. Rosen was a Popperian of sorts, and at that time held that the lack of falsifiability meant that “it explains everything, and therefore, nothing”. He several times quotes Waddington, including the comment that “The whole real guts of evolution—which is how you come to have horses and tigers and things—is outside of the mathematical theory” (1967).

Robert Peters (1976), taking as his criteria for scientific theories the ideas of the logical positivists, argued that tautology is nonexplanatory in a scientific theory because it is not empirical. Hence, natural selection, and fitness, which are tautologies, are nonexplanatory; however, they are useful. He conflates, as many have, the theory of evolution, and the principle of natural selection. Peters’ paper generated a response from G. Ledyard Stebbins, a leading botanist and one of the founders of the modern synthesis (1977). Stebbins pointed out that the historical nature of evolution is falsifiable, that the randomness of mutation does not mean evolution is entirely unpredictable, and that the axiomatisation of evolution by Mary B. Williams (1970) merely showed that if the conditions the axioms describe are realised, then evolution is the expected result, not that it is a tautology. The if-then-ness of these mathematical models plays a crucial role in this debate, as we shall see later.

The philosophical literature that followed is extensive. Let me mention some highlights (outlined in Grene and Depew).

There are basically two tacks taken to deal with the tautology problem. One is to argue that natural selection is not a tautology at all, but is a falsifiable set of conditions that hold true in some cases but not all. The other is to redefine “fitness” so that it has some non-tautologous truth conditions. To achieve this, fitness was changed from actual reproductive frequency to expected reproductive frequency. In other words, fitness was a dispositional property but not a determinate one, and was defined more or less mechanically – certain traits or variants will do better than others in a relative environment because they cause more progeny on average than the other alternatives in a population. Since we want natural selection to be a causal explanation rather than a formal one, this eliminates the problem.

Then the fun began – what is an expected fitness? How do we identify what that is? How can a disposition be causal? and so forth. Some philosophers argued that in fact natural selection, or survival of the fittest, really is a tautology after all; it’s a class of things that happen to realise fitness in multiple ways. Fitness, supervening on the biological and physical properties of actual organisms, Waddington’s horses and tigers and things, is an abstraction that is defined just in virtue of what the organisms do. An attempt to make functions propensities to behave likewise ran into these difficulties.

Recently there has been an attempt to make natural selection a mechanism for much the same reasons: if it is not a mechanism, how can it explain evolution (or at any rate, that part of it that is selectively biased)? Others think that fitness and selection are not real processes. Some think they are “force laws” that explain change, but which, like the physical laws of Newtonian physics can be plugged in with whatever objects are interpretable that way – a bird or a rock or a tissue in a vacuum all follow the first and second laws. The laws themselves are idealisations that describe the natural states, as it were, and so set up the things to be explained. According to Sober, Darwinian dynamics are a way to establish both what the “natural states” are, and to highlight the changes that need explanation.

This goes to a more general problem in science: how is it that mathematical models of anything have an explanatory power? For instance, if I give a Newtonian explanation of the orbit of a secondary around a primary in terms of the equations of Newtonian physics, how have I explained anything? I still do not have a mechanical explanation of gravity. And yet Newton’s laws, and later Einsteinian equations, were held to be excellent explanations. I’ll get back to this, but right now this is getting too long.

I’ll come back to this post later and add in more references, but work calls.

References

Bethell, Tom. 1976. Darwin’s mistake. Harper’s Magazine 252:70-75.

Garvey, Brian. 2007. Philosophy of biology, Philosophy and science. Montreal: McGill-Queen’s University Press.

Grene, Marjorie Glicksman, and David J. Depew. 2004. The philosophy of biology: an episodic history, The evolution of modern philosophy. Cambridge: Cambridge University Press.

Gould, Stephen Jay. 1976. This View of Life: Darwin’s Untimely Burial. Natural History 85:24-30.

Gould, Stephen Jay. 1977. Ever since Darwin: reflections in natural history. New York: Norton.

Macbeth, Norman. 1971. Darwin retried: an appeal to reason. Boston: Gambit.

Peters, Robert Henry. 1976. Tautology in Evolution and Ecology. The American Naturalist 110 (971):1-12.

Rosen, Donn Eric. 1978. Review: Darwin’s Demon. Systematic Zoology 27 (3):370-373.

Stebbins, G. Ledyard. 1977. In Defense of Evolution: Tautology or Theory? The American Naturalist 111 (978):386-390.

Waddington, Conrad H. 1967. Discussion, Paper by Dr Eden. In Mathematical Challenges to the neo-Darwinian interpretation of evolution. Philadelphia: Wistar Institute:12-19.

Williams, M. B. 1970. Deducing the consequences of evolution: a mathematical model. Journal of Theoretical Biology 29:343-385.

6 Comments

  1. Miles Miles

    Maybe this is due to ignorance or obtuseness on my part, but I am unable to understand how Gould’s reply to Bethell constitutes a rebuttal of the charge of tautology. In “Darwin’s Untimely Burial,” the crucial paragraph reads thus: “My defense of Darwin is neither startling, novel, nor profound. I merely assert that Darwin was justified in analogizing natural selection with animal breeding. In artificial selection, a breeder’s desire represents a ‘change in environment’ for a population. In this new environment, certain traits are superior a priori; (they survive and spread by our breeder’s choice, but this is a result of their fitness, not a definition of it). In nature, Darwinian evolution is also a response to changing environments. Now, the key point: certain morphological, physiological, and behavioral traits should be superior a priori as designs for living in new environments. These traits confer fitness by an engineer’s criterion on a good design, not by the empirical fact of their survival and spread. It got colder before the woolly mammoth evolved its shaggy coat” (Ever Since Darwin, p. 42).

    What does it mean to say that certain traits are “superior as designs for living in new environments”? Gould seems to mean that a trait can be judged to be superior to another trait in “design” independently of whether it is more widely transmitted than the other. How so? What is the “engineer’s criterion on a good design” to which Gould refers? Since Gould does not explain his point further, it must be either that I am missing something fairly obvious or that he is offering nothing more than a verbal runaround in the manner of Molière’s famous physician.

  2. b9n10nt b9n10nt

    Well, this is the internet, so for some untrained and untested musings:

    If I say, “Earthquakes push some ground up”, that’s a tautology (an inherent property of quaking). But if I allow the statement as a summary of genuine insights, there’s no problem with the tautology as such.

    Let’s say that the tautology conceals some accepted and relevant observation about quakes: they are locally-recurring natural phenomena whose effects on ground level can be cumulative (as opposed to cancelling).

    Let’s also say that the statement “Earthquakes push some ground up” is, in context, usually meant to precede the conclusion that earthquakes build mountain ranges.

    If, for social/historical/neurological reasons the earthquake theory of mt ranges was commonly summarized as “Earthquakes push some ground up”, wouldn’t we have an analogous situation (a summary of a scientific theory that, standing alone, could be critiqued as merely a tautology).

    Survival of the fittest, similarly, both summarizes several constituent, non-self evident observations and precedes (or implies the precession of) the idea that survival of the fittest is a natural cause of evolution.

    Survival of the fittest is a tautology, but the statement inevitably is used in the context of Darwin’s theory of evolution, unifying insights about bio populations and the evolution of species.

    I’ll call this the ‘context’ rejoinder to the tautology critique.

    Another rebuttal I can imagine is the “object critique”. Darwin does not establish survival of the fittest, for a tautology can not be established scientifically. But what is it that survives/doesn’t survive and has relevance to evolution? Not the organism, nor its descendents. It is traits/adaptations/characteristics that show variation and are “struggling”. Yes, organisms show the survival of the fittest. But components of organisms, traits, show survival of the fittest too. This change of focus that makes traits, not organisms, the object of the statement “survival of the fittest” is relevant and non-self-evident.
    so that’s the object rebuttal.

    The rebuttal Richard Wright (if I remember correctly) mentioned earlier, which defines fitness as a property of a trait that causes its own suvival in a population, seems problematic. How do we determine, beforehand, whether a trait is indirectly causing its own replication? How can we in fact distinguish a trait that is causing its own increase in frequency within a population from one that is only “along for the ride”? It seems that we have a logical solution to the tautology problem, but not a scientific one.

  3. ckc (not kc) ckc (not kc)

    How can we in fact distinguish a trait that is causing its own increase in frequency within a population from one that is only “along for the ride”?

    “causing its own increase” is a strangeish way of phrasing this (for one thing, increase is relative – perhaps other traits are “causing their own decrease”), but “along for the ride” compounds the vagueness. We may not know precisely how genotypes are translated into the phenotypes upon which selection (and drift, etc.) act, but to the extent that there is a connection, and not all phenotypes are proportionally represented in subsequent generations (nor their genotypes), the problem is surely not a logical one, but a scientific one – namely, why? (And sometimes the why is descriptive, and sometimes, we would wish, predictive – i.e. “beforehand” – though both why’s contribute to our understanding of what is not a tautologous problem/process.)

  4. b9n10nt b9n10nt

    ckc

    Thanks for taking the time for helping me think through this.

    It was Jim Harrison, not Richard Wright, who recently wrote on “The Tautology Problem” post:

    “Where there is no causal connection between a character and its increasing or decreasing occurrence over time, natural selection simply has not occurred.”

    It sounds like we agree that, in your words, “the problem [of why an allele or a phenotype gains in relative frequency] is surely not a logical one, but a scientific one”.

    My suspicion is that this is a scientific problem in that a scientist would have no means to go beyond descriptive causation, or to test alternative hypotheses about an increase in relative frequency.

    I’m sure I haven’t thought this through well enough.

  5. My understanding of Waddington’s take on this is a little different. Waddington held that “survival of the fittest” did not become a tautology until it was rescued by the neo-Darwinian population geneticists. Darwin (says Waddington) wrote as though fitness was a positive trait, something akin to strength or resiliency. But Fisher, Wright and Haldane (continues Waddington) generalized the concept mathematically so that it didn’t signify anything more than leaving differentially more offspring, which does not inhere to any single positive trait, and here the truism was born.

    Shortly before he died Waddington had a conversation with Maynard Smith (reprinted in Evolution of an Evolutionist) rehashing the tautology argument, where he made the further point that the neo-Darwinian mathematical models obscure the fact that there are no actual “laws of heredity” (which I take to be at least part of Fodor’s argument against natural selection.)

  6. Bill Bill

    Robert Henry Peters responded to Stebbins, and Castrodeza, C. 1977. Tautologies, beliefs and empirical knowledge in biology. Amer. Natur. 111:393-394 and Ferguson, A. J. 1976. Can evolutionary theory predict? Amer. Natur. 110: 1101-1104.

    This can be found in a follow up paper “Predictable Problems with Tautology in Evolution and Ecology”. The American Naturalist, Vol. 112, No. 986 (Jul. – Aug., 1978), pp. 759-762.

    He knocks all Stebbins and Ferguson’s main arguments down and concludes:

    “In summary, I should reiterate that the general theory of evolution through natural selection is tautological because it defines fitness in terms of differential survival, although other problems, such as the historical dimension, do exist. Specific theories may be predictive because they define fitness independently (e.g., the capacity to burrow), but their falsification cannot affect the general argument, since in all cases the fittest are, always and only, those which survive.”

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