Why look — it happens every time! Writing in National Review Online in December of last year, conservative commentator Tom Bethell expressed the main point more clearly:. But which ones are the fittest?
- A Book Of Five Rings.
- Is Natural Selection a Tautology? | Skeptical Inquirer?
- Il Signor Esagerato (Italian Edition)?
The ones that survive. There is no criterion of fitness that is independent of survival. Emphasis Added. Even before considering the minutiae of how fitness is defined, we should note something suspicious about this argument. Coulter and Bethell are not saying here that recent discoveries have shown that evolution is an inadequate theory.
Rather, they accuse scientists of having made a simple logical oversight. We are always ready to watch a theory fall under the impact of new data, but we do not expect a great and influential theory to collapse from a logical error in its formulation. Scientists are fully capable of jumping to conclusions, or arriving at incorrect theories from an inadequate supply of data.
But it has never once happened in the history of science that a theory achieves mainstream status, only to fall apart when a clever outsider notices a simple logical oversight.
Is Natural Selection a Tautology? | Skeptical Inquirer
Let us begin our reply to this argument in the most direct way possible. It is asserted that within evolutionary theory, the fittest organisms are defined as those who survive. This is the crux of the argument, and it is completely incorrect. In reality, the fittest organisms are the ones who, based on their physical characteristics and the environment in which they find themselves, would be expected to leave the most offspring.
Gould described the point this way:. 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 nature, Darwinian evolution is also a response to changing environments. Now, the key point: certain morphological, physiological and behvioral traits should be superior a priori as designs for living in new environments.
It got colder before the wooly mammoth evolved its shaggy coat. Let us imagine that we have perfect information about the environment in which a population of organisms finds itself. Let us further suppose that we are aware of the full range of extant heritable variation within the population. In those circumstances we could make some definite statements about the future evolution of that population.
A group of scientists could examine that information and come to a consensus about which members of the population were the fittest.
Reconsidering the logical structure of the theory of natural selection
Plainly there are criteria for fitness independent of mere survival. This is not the whole story, however.
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- Survival of the Fittest;
- The Prophecy Fulfilled;
- Word of the Day: Tautology.
Predicting the future is only a very small part of what evolutionary biology is all about. Most of the interesting events in evolution took place in the distant past. Unraveling and explaining that past presents scientists with a problem almost perfectly opposite to the one considered in the previous paragraph. Instead of trying to predict the future evolution of a species given information about its present environment, now we are trying to understand ancestral environments given information about what sorts of creatures survived.
In this context scientists will, indeed, hypothesize that traits that persisted and developed over long periods of time did so because of the fitness advantages they conferred on their possessors. The assumption that the trait under investigation emerged from the prolonged result of natural selection is used to generate testable hypotheses about the creatures in question. Williams provides the following example:. Productive use of the idea of functional design, in modern biological research, often takes this form: an organism is observed to have a certain feature, and the observer wonders what good it might be.
For instance, dissection and examination of a pony fish shows it to have what looks like a light-producing organ, or photopore, and even a reflector behind it to make it shine in a specific direction. It it really reasonable to define fit as "those who survive"? Certainly if you use that definition then the statement "only the fit survive" or "survival of the fittest" becomes "only the survivors survive" or "survival of the survivors", a tautology.
But that doesn't make much sense when you think about it, does it? One wouldn't normally use the word "fit" to mean only that some person or animal had survived. That is, the faster running cheetah, for example, who is more capable of capturing prey, therefore more likely to live longer and have more offspring. The question asked above is "how can you tell which are the fit animals". Well, if the fit animals tend to survive and have more offspring than the 'less fit' one way to tell which animals are fit is to look at the ones that had more offspring But doesn't that make the above author correct?
Doesn't that mean that "fit" is defined as "survivor" and therefore Darwinian evolution is based on a meaningless tautology? No, it does not. Looking at the set of survivors is one way to tell which animals are fit. However, the fact that the animals survived does not determine or define their fitness. Consider a different law: "drinking of the thirsty. So, how can we determine who is thirsty? Now consider this statement: The answer is that the only way to define the thirsty is by means of a post-hoc rationalization -- the thirsty must be those who drank. That is certainly not the case.
Being thirsty is a real condition which causes people to drink. Thus we can determine who is thirsty by looking at who drinks, but that does not mean that being thirsty simply means drinking. Similarly, being fit is a condition which tends to lead to higher survival rates, and thus larger numbers of offspring.
- An Old Man Who Lived at the Bottom of a Tree.
- Poetry, Worte, die von Herzen kommen (German Edition).
- The tautology problem – Evolving Thoughts.
- The Army of God: The Church;
- Is "Survival Of The Fittest" A Tautology?.
- Misericordia (Edición definitiva preparada por la Real Academia Española) (Spanish Edition).
Thus we can determine who is fit by looking at who survives, but this does not mean that being fit simply means surviving. So what does "fit" mean? How can we tell independent of survival rates or number of offspring which animals are more fit and which are less fit?
Survival of the fittest
The answer is that it is next to impossible in practice. It seems reasonable at first glance to say things like "a cheetah that can run faster is more fit", but perhaps being able to run faster comes at a cost. Perhaps the cheetah's bones are too thin and likely to break.
Perhaps the amount of extra energy the faster cheetah uses to capture a meal is out of proportion with the energy provided by extra meals caught because the animal is faster. Tradeoffs like that are one reason why cheetahs do not run at the speed of sound. However, it is possible in principle to determine the fitness of an animal. One would have to be nearly omniscient in order to calculate all the tradeoffs and all the effects of a particular characteristic, but in the end a characteristic is either helpful to an animals chances to survive and therefore makes the animal more fit or not.
In the real world nobody needs to perform all these calculations. We, and the other animals, are born with certain characteristics and potentials, we develop, live, have children or not , and die. Nobody needs to calculate which animals are fit, but their characteristics certainly do have an effect on their chances to live and the number of offspring they might have which will inherit those characteristics, to some extent. Nature does not calculate what it is going to do, it simply does. To claim that the "survival of the fittest" is a meaningless tautology, and so Darwinian evolution is meaningless or impossible, is to claim that inherited characteristics, like speed or strength, color of fur or plumage, and so on, are irrelevant to the chances for an animal to survive, have many offspring, and pass on those characteristics to it's offspring.
That claim is simply false. I do want to address a second passage from the www. George Simpson, professor of paleontology at Harvard, [said] "If genetically red-haired parents have, on average, a larger proportion of children than blondes or brunettes, then evolution will be in the direction of red hair. If genetically left-handed people have more children, evolution will be towards left-handedness.