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Vol. II • 1979

Karl Popper's Challenge
By Russell Kranz

Is the theory of evolution scientific?

Not according to the eminent philosopher of science, Professor Karl Popper This is all the more interesting because Charles Darwin was an Englishman and Dr Karl Popper is an adopted Englishman with a string of scientific accomplishments that fill half a column in the International Who’s Who. After a hundred years of evolution, what does this respected scientist think of his countryman's theory?  

Not much that Darwin would like.

"Darwinism is not a testable scientific theory," Popper says, `but a metaphysical research programme."1

Popper's views are widely respected in Europe and particularly in England, where he has come to be regarded as one of the most important philosophers of the twentieth century. Sir Peter Medawar rates him as "incomparably the greatest philosopher of science that has ever been."2 Another well-known mathematician and astronomer says, "There is no more to science than to its method and there is no more to its method than Popper has said." Popperian influence can be seen in medicine, in art even in politics and theology. Leading politicians have expressed their indebtedness to him.  

Not a Law

Professor Popper is severely critical of attempts to turn evolution theory into scientific fact. "There can never be a law of evolution," he wrote in one of his earlier works.3 "The idea of a law which determines the direction and character of evolution is a typical 19th century mistake arising out of the general tendency to ascribe to the natural law the functions traditionally ascribed to God."4

What happened then, he says, was this: "The earlier, naturalistic revolution against God replaced the name God by the name Nature. Almost everything else was left unchanged. Theology. the science of God, was replaced by the science of nature. God’s laws by the laws of nature. God's will and power by the will and power of nature (the natural forces) and later God's design and God's judgment by natural selection. Theological determinism was replaced by naturalistic determinism, that is. God's omnipotence and omniscience were replaced by the omnipotence of nature and the omniscience of science."5  


Why has Popper separated evolution from science and assigned it to the realm of metaphysics? According to Popper's principle of demarcation, only those theories which are open to empirical falsification are scientific. That is, unless there is a way to prove a theory wrong there is no way to prove it is right. As he puts it: "Statements or systems of statements in order to be ranked as scientific must be capable of conflicting with possible or conceivable observations."6 Science deals with matters that can be tested empirically and are potentially falsifiable. "Since we should call empirical or scientific only such theories as can be empirically tested, we may conclude that it is the possibility of an empirical refutation which distinguishes empirical and scientific theories."7 (By empirical, Professor Popper means that which can be tested by the senses - weighing, seeing, touching, tasting, measuring, etc.)

Now, philosophical or metaphysical theories are empirically irrefutable by definition, There is simply no way to test them in laboratory conditions, Popper is prepared to admit that the line of demarcation is not absolutely sharp. There are degrees of demarcation - well-tested theories, hardly testable theories and nontestable theories. The latter, he insists, do not belong to science: "Those which are non-testable are of no interest to empirical scientists. They may be described as metaphysical."8

And it is in this "non-testable" category that Popper places evolution, Science is just not equipped to deal with the question of origins. "The search for the law of "unvarying order' in evolution cannot possibly fall within the scope of scientific method, whether in biology or sociology."9  


Simply because if the evolution of life on earth did occur, it was a unique historical process which cannot be tested because it is unrepeatable. "We cannot hope to test a universal hypothesis nor find a natural law acceptable to science ifwe are forever confined to the observation of one unique process. Nor can this observation of one unique process help us to foresee its future development."10  

Repeating Itself

In several of his later lectures Professor Popper finds fault with the theory of evolution on the grounds that it is tautological; it repeats itself.

Natural selection explains evolution in terms of the survival of the fittest, But he points out that this is really no more than saying, "Those that survive are those that survive. Darwinism, therefore, "is by no means a perfect theory."11 When all is said and done, "neither Darwin nor any Darwinian has so far given an actual causal explanation of the adaptive evolution of any single organism or any single organ. All that has been shown is that such explanations might exist (that is, to say) they are not logically impossible."12

Evolutionists often try to rescue their theory by adopting a device which makes it irrefutable. By pushing back the frontiers of time, anything becomes probable. Dr. Popper objects strongly.

"Statistical explanation must operate in the last analysis with very high probabilities. But if our high probabilities are merely low probabilities which have become high because of the immensity of the available time, then we must not forget that in this way it is possible to explain almost everything. Even so, we have little enough reason to conjecture that any explanation of this sort is applicable to the origin of life."13

Popper also returns to his argument about the tautological nature of Darwinism. "At first sight, natural selection appears to explain the evolution of variety - and in a way it does; but hardly in a scientific way."" Adaptation or fitness is defined by modern evolutionists as survival value and can be measured by actual success in survival: there is hardly any possibility of testing a theory as feeble as this."14  

Metaphysical Differences of Opinion

Yet, despite his criticism Popper thinks Darwin's theory has been valuable in encouraging some very real and practical researches. That is why it has been so widely accepted. There could be another reason too. It was the first non-theistic theory that was convincing. "Theism was worse than an open admission of failure, for it created the impression that an ultimate explanation had been reached."15

At this juncture, Karl Popper makes a very interesting comment. "Now to the degree that Darwinism creates the same impression it is not very much better than the theistic view of adaptation." "It is therefore important to show that Darwinism is not a scientific theory, but metaphysical."'6

So what for the last hundred years has appeared as a conflict between religion and science is simply a difference of metaphysical opinion. No doubt Popper's insistence on the nonscientific nature of evolution will come as a surprise to those who cling to outmoded definitions of science, You don't settle metaphysical disputes in the laboratory. On the issue of origins the last word definitely does not belong to the scientists.

It now looks as if the whole evolution/creation question will have to be reappraised in the light of purpose and meaning. I, for one, am convinced that when it comes to providing man with a metaphysical framework in which to view his living experience, the simple biblical explanation of human existence does much greater justice to freedom, moral responsibility, equality. the dignity of man, conscience, truth and other values than any explanation based upon the survival of the fittest.

1 Karl Popper, Unended Quest (Glasgow: Fontana, Collins. 1976), p.151.
2 BBC Radio 3, July 28, 1972.
3 Karl Popper, The Poverty of Historicism (London: Routledge & Keegan Paul, 1972), p. 108.
4 Karl Popper, Conjectures and Refutation (London: Routledge & Keegan Paul, 1972), p. 340.
5 Ibid., p. 347.
6 Ibid., pp. 38.39.
7 Ibid., p. 197.
8 Ibid., p. 257.
9 Popper, The Poverty of Historicism, p.108.
10 Ibid.
11 Karl Popper, Objective Knowledge (Oxford: Clarendon Press, 1975) p. 242.
12 Ibid., p. 267.
13 Popper, Unended Quest, p. 169.
14 Ibid., p.171.
15 Ibid., p.172.
15 Ibid.

"Karl Popper's Challenge"
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