Is the famous tautology argument against Darwinism valid?
Thanks to Mr. Hechtman for his brutal honesty in the latest Darwin discussion. He writes:
“Before you ask, yes, Darwinians do know that that makes it a circular definition and yes, we do find that vaguely unsatisfying. But what are we going to do? Contradict the great prophet Darwin?”
This captures the problem nicely: what would count as either confirming or disconfirming evidence? Why did organism “X” appear? Because it was “fit.” What makes it “fit”? Its appearance.
Of course, we include the proper statistical qualifications … and to a degree sufficient for intimidating the unwitting person who senses something ain’t kosher. But dress it up a thousand ways … and dress it up they do … and the circle is still there.
I’ve read a fair share of philosophy of biology … I’ve always wanted to know why the circularity problem here isn’t a disqualifying one for any would-be scientific theory. I’m still waiting to hear a good answer.
The example with which this thread began is a good instance of what they like to call the “units of selection” problem.
Just what is being “selected for”? Individuals? Groups? Genes?
Years ago, when I was still trying to salvage something of Darwinism, a friend (an atheist to boot) convinced me that this question is entirely metaphysical, and not properly scientific. Yet, it would seem to be an inescapable issue for any cogent Darwinian account of things. I didn’t want to believe it at the time, but I came to accept his position.
I have to confess that I have never been persuaded by the circularity argument against Darwinism. I don’t think that the Darwinian theory of the survival of the fittest is tautological, i.e., that it repeats the same sense in different words, and thus is meaningless. Yes, it seems tautological if phrased in a certain way. Thus when you write,
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Why did organism “X” appear? Because it was “fit.” What makes it “fit”? Its appearance.
I agree that that seems like circular reasoning. But that’s not actually what Darwinian theory says. The theory says that an organism has some variation or mutation that differentiates it from the rest of its fellow species members living in the name environmental niche. Perhaps the change enables the organism to repel a certain parasite, or to absorb more needed Vitamin D from the sun, or to retain body heat better in a cold environment. Whatever the variation or mutation may be, the organism has it, and its bros in the hood do not have it, and as a result, this organism survives and has offspring, while many of its compatriots die without reproducing. After this filtering process is repeated each generation for a number of generations, all the species members in that environment have that feature.
I don’t think that this argument or theory is circular. It only becomes circular when we treat “fitness” as an abstract concept, e.g., “An organism survives because it is more fit, and the proof that it is more fit is that it survived.” If we avoid the abstract language about “fitness” and speak in concrete terms, e.g., “Organisms possessing allele X survived at a higher rate than organisms without allele X, and, as a result, over several generations allele X became dominant in the population,” then I think we’ve dispensed with circularity.
The problem with the Darwinian argument about mutations improving the survivability of the possessor and thus being selected and becoming dominant in the species is not that it is circular and thus logically meaningless. The problem with the Darwinian argument is that in the overwhelming majority of cases it can never be factually demonstrated. It’s pure guess work. No one knows, and no one can know, that a certain mutation enabled its possessor to live longer.
Yes, we have very suggestive evidence in some instances, for example, the fact that people in the tropics have dark skin and people in the northern latitudes have light skin. But in the great majority of discussions of evolution, the supposed mutation that led to the supposed natural selection of a new feature is nothing but a speculative guess masquerading as science.
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Note: anyone who thinks I am defending Darwinism should read again. I am not saying that the statement, “New species evolved via the survival of the fittest,” is true. I am saying that the statement is not inherently meaningless.
Aaron S. replies:
Fair enough. Maybe we’re agreeing after all is said and done, but I think I’m expressing this from a somewhat different angle.
You’re right that the theory does not state things in the slightly sarcastic and overly simplistic way that I have. The question is whether, in order to defend themselves from the charge of excessive looseness in their concepts—or perhaps from the charge of arbitrarily injecting some teleological notion into their scheme, Darwinians must fall back on something like my formulation.
Maybe one way we could put the problem is this: what exactly could “fitness” mean as an empirical concept? As I see the situation, it either IS a teleological notion, or it is not. If it is not, I don’t see how we avoid circularity—mathematical accounts are after all just descriptions of the relative presence or absence of traits, organisms, etc. . The thing is, when pushed, most Darwinists seem to define “fitness” in mathematical/statistical terms—gene frequency and such—as they seem to think this move rescues them from the conundrums of discussing purpose.
The problem is that every narrative they concoct for the emergence of a new organism makes use of teleological structure, i.e., THIS trait was advantageous in THAT set of circumstances… but what exactly is advantage? Go beyond numerical measures of reproductive success and what are you left with? Some nonscientific *judgment* or other is injected arbitrarily.
They argue about possible mechanisms—but what could serve as evidence for such things? My point in bringing up units of selection is that the problem for them is even deeper than this. Forget mechanisms—they can’t even agree as to how we’d distinguish what *thing* is subject to the forces of selection.
So I’d say that the problem is not specifically that the theory is circular. It is *either* circular or wildly speculative (to the extent of standing outside of any possible testing). The Darwinist under attack will lean to one side or the other depending upon the nature of the question leveled at him.
I don’t understand your comment very well. I always have difficulty with this “tautological” issue, because it seems to me that everyone who deals with it keeps using abstract phrases without clearly explaining what they mean, a major problem with modern intellectual life. But I’ve posted your comment. Maybe others will follow it better than I do.
I think the problem that you are criticizing comes from seeking some abstract definition of fitness. So, if we get away from the abstraction and just consider the Darwinian scenario itself, are you saying that it is logically meaningless (tautological) to say that an organism that has a particular mutation may reproduce, while most of its fellows who do not have that mutation to not reproduce, and that over generations that mutation becomes dominant in the population? Where do you see a problem in this assertion? (Again, not whether it’s true or not, but whether it is has an intelligible and coherent meaning or not.)
Ken Hechtman writes:
“This captures the problem nicely: what would count as either confirming or disconfirming evidence? Why did organism X appear? Because it was fit. What makes it fit? Its appearance.”
The circular definition isn’t quite that. I’m quoting my professor from an evolutionary biology class I took almost 20 years ago: The organisms that survive and reproduce their genes are defined as “fittest” and fitness is defined as “the ability to survive and reproduce.” She admitted it was a lousy definition but it’s the one we’re stuck with.
Aaron S. writes:
I agree that the scenarios here—and indeed most of the ones the Darwinians offer—are logically coherent. I can imagine such things, and there seems to be no logical contradiction in doing so.
But logical coherence does not a scientific theory make—or at least few people have said so since the high rationalist age. At some point, you’ve got to put forth a proposition, or a set of them, that can stand in some clear relation to empirical evidence. On this count, Darwinians bash “creation science,” and rightly so.
This is what I meant by talking about “fitness” as an empirical concept. It should be—if not abstract—then general. Otherwise, each scenario describes a completely separate and distinct event, and it ends there. Barring the invention of a time machine, we’re done. In genuine science this isn’t a problem—don’t we explain things scientifically by comprehending (that is, bringing separate events under a common heading, rule, or pattern)? Past events can be examined in their relation to present and future ones, to which questions can be put—according to general propositions that serve as testable hypotheses.
But if fitness is entirely particular, there’s nothing more to say. It doesn’t matter that I can imagine environmental circumstances leading to changes in populations due to possession of genotypic or phenotypic traits. I can also imagine the world literally coming into existence in six days.
Darwinians will counter that theirs is the least improbable conjecture on offer. I’m not sure of that, but even if they are correct, I don’t see how that alone renders their stories scientific.
This is very intelligent and well written, but I’m not sure you ever come to a point. You seem to come close when you say, “This is what I meant by talking about ‘fitness’ as an empirical concept,” but then you immediately go off on side issues and leave everything hanging. So, if I may ask, assume you’re talking to a person who has difficulty understanding things—e.g., me—and that you have to make your point really clear in order to reach him.
Posted by Lawrence Auster at May 29, 2009 05:33 PM | Send