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Section 3: Quotations from Scientists

Science, Religion, Creation and Evolution

Does Evolution Meet the Criterion of Falsifiability

Karl R. Popper, Federation Proceedings, American Societies for Experimental Biology, Vol. 22, 1963, p. 964.

There is a difficulty with Darwinism. While Lamarkism appears to be not only refutable but actually refuted (because the kind of acquired adaptations which Lamarck envisaged do not appear to be hereditary), it is far from clear what we should consider a possible refutation of the theory of natural selection. If, more especially, we accept that statistical definition of fitness which defines fitness by actual survival, then the survival of the fittest becomes tautological, and irrefutable.

Darwin's great achievement was this, I believe. He showed that what appeared to be purposeful adaptation may be explained by some mechanism--such as, for example, the mechanism of natural selection. This was a tremendous achievement. But once it is shown that a mechanism of this kind is possible, we ought to try to construct alternative mechanisms, and then try to find some crucial experiments to decide between them, rather than foster the belief that the Darwinian mechanism is the only possible one.

Karl R. Popper, Unended Quest (Revised edition) (Open Court Publishers, La Salle, Ill., 1976), p. 168.

...I have come to the conclusion that Darwinism is not a testable scientific theory, but a metaphysical research programme--a possible framework for testable scientific theories.

Ibid., pp. 171-172.

And yet, the theory is invaluable. ...it suggests the existence of a mechanism of adaptation, and it allows us even to study in detail the mechanism at work. And it is the only theory so far which does all that.

This is, of course, the reason why Darwinism has been almost universally accepted. Its theory of adaptation was the first nontheistic one that was convincing; and theism was worse than an open admission of failure, for it created the impression that an ultimate explanation had been reached.

Now to the degree that Darwinism creates the same impression, it is not so very much better than the theistic view of adaptation; it is therefore important to show that Darwinism is not a scientific theory, but metaphysical. But its value for science as a metaphysical research programme is very great, especially if it is admitted that it may be criticized, and improved upon.

L.C. Birch and P.R. Ehrlich, "Evolutionary History and Population Biology," Nature, Vol. 214, 22 April 1967, p. 349.

...to...attempt to investigate ecology and taxonomy through a series of inferences about the past is to base these sciences on non-falsifiable hypotheses....All that is accomplished by those who feel that evolutionary history is the only pertinent aspect of population biology is a confusion of data and untestable hypotheses.

Ibid., p. 351.

...the phylogenetic speculation...about the relative times of divergence of butterfly and plant groups, the past significance of secondary plant substances, and so on--are of no help whatever in explaining present day ecology. They are a series of unfalsifiable hypotheses. These hypotheses do not help us to understand the distribution and abundance of plants and butterflies today, because they are not subject to testing.

Ibid., p. 352.

Our theory of evolution has become, as Popper described, one which cannot be refuted by any possible observations. Every conceivable observation can be fitted into it. It is thus "outside of empirical science" but not necessarily false. No one can think of ways in which to test it. Ideas, either without basis or based on a few laboratory experiments carried out in extremely simplified systems, have attained currency far beyond their validity. They have become part of an evolutionary dogma accepted by most of us as part of our training.

Sir Peter Medawar in Mathematical Challenges to the Darwinian Interpretation of Evolution (The Wistar Institute Press, Philadelphia, 1967), p. xi.

...Then, there are philosophical or methodological objections to evolutionary theory. They have been very well voiced by Professor Karl Popper--that the current neo-Darwinian Theory has the methodological defect of explaining too much. It is too difficult to imagine or envisage an evolutionary episode which could not be explained by the formulae of neo-Darwinism.

Sir Peter Medawar in Studies in the Philosophy of Biology, F.J. Ayala and T. Dobzhansky, editors (University of California Press, Berkeley, 1974), p. 363.

I should like to address some comments about this equally to Jacques [Monod] and Doby [Dobzhansky]. It seems to me that there is a real methodological weakness in the modern evolution theory for which Dobzhansky is largely responsible. It explains too much. It has such an enormous experimental facility that one could hardly imagine anything it could not explain. Now the danger of this is that it rules out any incentive to inquire about any other possible mechanisms that could explain the observed facts. In this sense, the evolution theory is like psychoanalysis. If any young man started off with a starry look in his eye saying that he wanted to inquire into the mechanisms of evolution I think he would be like the young research student you referred to, Jacques, who was looking for working class enzymes in that theory. They would think he was mad. But there is a point there. Can you actually test (you can in microorganisms of course)--can you test this kind of theory? It is very difficult to test it, say disprove it, or even having the possibility of disproving in higher organisms the kind of evolution theory that you, Dobzhansky, have done so much to establish.

Jacques Monod, ibid., p. 363.

Well, I think, Peter, that I agree with you that the explanatory power of modern evolution theory is very great. In other words, it has the weakness of not being highly vulnerable to experiment. But the reason it is not very vulnerable to experiment is not because of the structure of the theory itself but because of the kinds of experiments that would have to be done to falsify it. You see, according to Popper's criterion--and again, correct me if I am wrong, Sir Karl--the theory falls on the right side of the criterion, provided its structure is such that an experiment, including imaginary experiments, could be done to falsify it. Whether an experiment can actually be done or not is another matter. So it seems to me that as far as being falsifiable in principle the modern theory of evolution is falsifiable. That it is extraordinarily difficult to put it to actual experimental test, as opposed to observational test, is of course due to the immense amounts of time involved....

C.H. Waddington, "Evolutionary Adaptation," in Evolution After Darwin, Vol. 1, Sol Tax, Editor (University of Chicago Press, 1960), pp. 385-386.

...Natural selection, which was at first considered as though it were a hypothesis that was in need of experimental or observational confirmation, turns out on closer inspection to be a tautology, a statement of an inevitable although previously unrecognized relation. It states that the fittest individuals in a population (defined as those which leave most offspring) will leave the most offspring. Once the statement is made, its truth is apparent. This fact in no way reduces the magnitude of Darwin's achievement; only after it was clearly formulated, could biologists realize the enormous power of the principle as a weapon of explanation....

This explanation is a very powerful one. It could, in fact, explain anything....

Bruce Wallace, Chromosomes, Giant Molecules and Evolution (W.W. Norton & Co., Inc., New York, 1966), p. 5.

....Furthermore, we reject special creation as an adequate explanation because we can think of no means by which we can put it to a valid test, because we can imagine no observation falling outside the capabilities of a creator possessing unlimited ability. Search diligently for the adequate, reject the untestable--these are the recognized procedures of the laboratory, the classroom, the clinic, and the courtroom.

Ibid., p. 77.

...Rejecting as we must the untestable `explanation' of the origin of species through special creation....

Ernst Mayr, Mathematical Challenges to the Neo-Darwinian Interpretation of Evolution (Wistar Institute Press, Philadelphia, 1967), p. 47.

...most of this research dealt only with two factors, mutation and selection, in other words, the original Darwinian model. Popper is right; this model is so good that it can explain everything, as Popper has rightly complained.

Alex Fraser, ibid., p. 67.

...the only thing I have clearly agreed with through the whole day has been the statement made by Karl Popper, namely, that the real inadequacy of evolution, esthetically and scientifically, is that you can explain anything you want by changing your variables around.

Murray Eden, ibid., p. 71.

...This[i.e., experimental falsification of the theory--editor] cannot be done in evolution, taking it in its broad sense....It can, indeed, explain anything. You may be ingenious in proposing a mechanism which looks plausible to human beings and mechanisms which are consistent with other mechanisms which you have discovered, but it is still an unfalsifiable theory.

Everett C. Olson, Evolution After Darwin, Vol. 1, Sol Tax, editor (University of Chicago Press, 1960), p. 530.

Selection theory, to date, has been the most successful integrating concept that has been advanced. That no organic event has been discovered that cannot be explained by the "synthetic theory," or selection theory, as is often stated, is in a sense true. On the other hand, the feeling of a slight sense of frustration in the elasticity involved in developing a universal explanation is hard to avoid, a feeling somewhat in sympathy with V. Bertalanffy when he noted "a lover of paradox could say that the main objection to selection theory is that it cannot be disproved."

...The origins of these structures are often "explained" by abstract models that derive their principal data from "laws" of genetics, "laws" which may be under dispute by the geneticists themselves. The extent of assumption, interactions of assumptions, and the degrees of extrapolation give a sense of uneasiness when the animals and their structures are foremost in mind. Essentially, the student is faced with the following proposition: Given that certain "laws" of genetics are correct, a particular event or series of events must have taken place to produce a structure, if it be assumed that some particular set of conditions held during the course of production. Many genetic models, however, as Lerner has noted, go well beyond the evidence. they may not be trustworthy bases for the proposition. In the most given situations, however, some of the conditions that held during development can be deduced, even in paleontological studies, and there is good evidence that many of the genetic "laws" hold, at least over a small part of the organic world. But in most cases, detailed steps of development and details of the environment in which they took place are largely unknown. Thus, in explanation, it is usually true that we end up with several possible courses to the same end and that it is virtually impossible to choose between the several intelligently. In this sense, there is little or nothing that cannot explained under the selection theory, and, at present this theory appears to be unique in this respect.

Ibid., p. 531.

...It is not sufficient to show that something could have happened otherwise, but rather that it could not have happened under the formulation that is the synthetic theory. This is indeed difficult, and, for all the suspicions that some paleontologists and morphologists may have about the adequacy of the theory, there is very little that they can do to confirm these feelings on the basis of the types of analysis that their materials allow. This may be further generalized, to the effect that there is no known way of attacking experimentally some of the areas in which doubts of the sufficiency of the synthetic theory arise--areas, for example, not subject to analysis because of the time factor.

Ibid., pp. 535-537.

...The paleontologist...deals with morphology and sees order in its change. He witnesses major trends...He sees what appear to be highly adaptive types of organisms side by side with what appear to be adaptive "monstrosities." He sees groups of organisms, apparently in their prime, fade and disappear through "short" periods. And he may ask: "All this through shift in gene frequencies, in genetic shift through differential reproduction and slow change through successive populations?" Even though he may answer Yes, there still exists for many a feeling of remoteness between the concepts of evolution seen in the elegant genetic constructions of such students as Wright and Fisher and the equally penetrating considerations of morphology and evolution as displayed by paleontologists such as Romer, Watson, or Westoll. The efforts to bridge the gap leave a real feeling of remoteness at the operational level and in many cases a feeling that the explanations of genetics and selection are not significantly applicable to some of the types of phenomena observed in much of the fossil record.

...The point has been made that the very conciseness, consistency, and tightness of the synthetic theory, combined with the almost limitless flexibility due to the nature of the definition of selection, can lead to acceptance of generalizations not applicable over the whole range of evolution. This possible danger is amply revealed in some studies of the last decade which seem more concerned with fitting results into the current theory than with evaluation of results in terms of a broader outlook. Further, of course, much research is conceived and carried out within the framework of the theory, and, no matter what its excellence, it is not likely to break out of this framework....

...the important element of testing by experimentation is not possible with fossil materials. The fossil record, on the other hand, has been a source of data that have been considered by various students as somewhat contrary to the concepts developed in genetics and related fields and this in itself can be an important contribution. This evidence has been "explained" to the satisfaction of many, although not all. ...

John C. Fentress in Mathematical Challenges to the Neo-Darwinian Interpretation of Evolution (Wistar Institute Press, Philadelphia, 1967), p. 71.

...I would simply like to give one example which I think illustrates how important it is to ask a precise question. When I was in Cambridge, we were working with two species of British vole.

We had a little test in which an object moved overhead; one species would freeze. Also, one species happened to live in the field. This was rather fun, and, not really being a zoologist, I went up to see some of my zoologist friends and I reversed the data. I asked them, simply, why a species which lived in the field should freeze and why one that lived in the woods should run away (when the reverse was the case). I wish I had recorded their explanations, because they were very impressive indeed.

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