Karl Popper and Evolution: Is Evolutionary Theory Based on a Tautology?
In the September/October issue of Skeptical Inquirer, Massimo Pigliucci writes:
Perhaps the best-known philosophical criticism of evolution was put forth by Karl Popper, who once claimed that “Darwinism is not a testable scientific theory, but a metaphysical research program” (Unended Quest, 1976). ... Popper proposed his famous criterion of falsification to solve the demarcation problem: good science is done when hypotheses can be shown to be false (if they indeed are). That’s where the philosopher’s criticism of evolutionary theory originated from. Popper understood evolutionary biologists to say that their theory predicts that natural selection allows only the fittest organisms to survive; but, he countered, the “fittest” organisms are defined as those who survive, which makes the statement tautological.
Some creationists make similar criticisms today, but they fail to appreciate the fact that Popper retracted his criticism:
“I have changed my mind about the testability and logical status of the theory of natural selection; and I am glad to have an opportunity to make a recantation” (Dialectica 32:344-346).
Why the change? Because there are independent means for determining which members of species are “fittest.”
[B]iologists employ optimization analyses to predict which combinations of morphological, behavioral, or physiological traits are more likely to be advantageous (i.e., to increase “fitness”) in the range of environments actually encountered by a given living form. They then sample natural populations of organisms, determine in which environments they actually live, measure those traits they hypothesize are more likely to make a difference, and obtain statistical predictions on where natural selection should push the population next. Finally, biologists wait until the next generation of organisms comes out and measure their characteristics again.
Karl Popper was a philosopher rather than a scientist, but he demonstrated the scientific mindset: he changed his mind about a conclusion he reached once he was show new information which contradicted his beliefs. This often isn't easy to do because no one likes to be wrong; with some conscious work, though, a person can make it a bit easier and learn to accept their own fallibility.
We can contrast this with the creationists who so love to cite Popper or at least make the same arguments he did without acknowledging their debt to him. When confronted with information that contradicts their beliefs, they refuse to change their minds. Instead, they deny the evidence or rationalize ways to ignore anything they don't like. Creationists want to benefit from the thinking of Karl Popper without committing themselves the consequences of his skeptical, philosophical, and critical mindset. Even worse, it's seems unlikely that they have any idea what this means.
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You quote out of context. Popper recanted that natural selection is “almost a tautology”, thus affirming that it’s not “almost”, but completely, a tautology. Popper calls evolution “a metaphysical research programme” which means he believes it is philosophy not science and is not empirically testable:
“…I have tried to explain how the theory of natural selection could be untestable (as is a tautology) and yet of great scientific interest. My solution was that the doctrine of natural selection is a most successful metaphysical research programme.”
Popper never said evolution isn’t a taut, he restated that it is a taut, and his “recantation” is a tongue and cheek response to the attacks by evolutionists. Thus Popper’s claimed “recantation” is a philosopher’s sardonic response to criticism: with the pretense of apology Popper reaffirms his past statements, that evolution is “metaphysical” and hence not empirically testable.
Given the fact that he said he changed his mind, it’s clear that his recantation was genuine. That is as it should be, since natural selection and evolution are not only testable, but have been tested and have survived testing.
Ultimately, your argument is with Pigliucci and your allegation of quoting out of context is with him as well. I find his argument far more credible than your brief comment.
It’s impossible that I have a problem with Pigliucci and not you as well. Quoting someone who misquotes without acknowledging the misquote, IS misquoting. Now if Pigliucci is quoting out of context then so are you, since you neglect to acknowledge his quote is out of context. On the other hand, if he is accurate, then you are accurate as well. You can’t pretend you have no responsibility concerning the information you report just because you report what some one else said.
Has Popper recanted that NS is “almost tautological”, thus he means NS is a tautology, or does he mean he no longer thinks it is a tautology at all? We may interpret his words in different ways, but one thing is for sure, Popper still believes NS is metaphysical and hence not testable.
When I first read Popper’s recantation I took it literally. But there’s a part of what he says that doesn’t make sense when taken literally. If he truly recanted, and changed his mind, so that now he is saying NS is testable, why does he still call NS a metaphysical research program? Metaphysics may be based on empirical sense data, but its conclusions are not empirically testable in the same way as science.
When Popper says “I have changed my mind” we must make an inference about what Popper changed his mind about since he does not state this directly; hence that statement is open to interpretation. When Popper says “the doctrine of natural selection is a most successful metaphysical research programme”, no inference is required, since Popper directly tells us NS is a metaphysical doctrine.
Is Popper telling us that NS is both metaphysical and testable? This is a contradiction that either makes Popper into a moron, or suggests that Popper is sharing a ground breaking philosophical concept whereby metaphysics can be tested via the scientific method. Since Popper does not directly state what he has changed his mind about, to infer that Popper’s “I have changed my mind” means he believes NS is testable requires one of these two conclusions. Any interpretation of Popper is incomplete that claims he believes NS is testable while not addressing these conclusions.
However, there is a theory that makes sense of all the data in the simplest way. Popper is being sarcastic. Popper may no longer call NS a tautology, but he certainly claims it is not testable. At best he has replaced his original claim, that NS is a tautology, with the claim that it is metaphysical. He states directly, and multiple times, that NS is metaphysical. He says he has changed his mind, but he is ambiguous about what he has changed his mind about. Since he does not directly state his new opinion, but he directly states that NS is metaphysical (and Popper well knows metaphysics is not empirically testable), whatever we infer, it cannot be that Popper now thinks NS is testable.
To put it simply, we are witnessing the sarcasm of a philosopher. His “recantation” is sardonic because he seems to withdraw the claim that NS is a taut and hence not testable, and replace it with the claim that it is metaphysical and hence not testable. Sarcasm on paper is easily misinterpreted and can only be understood in context. That’s why the single quote “I have changed my mind…” is not enough to determine the meaning of his words. Only in isolation does this sentence mean that Popper thinks NS is testable. If Popper has recanted his statement that NS is a tautology, he has undoubtedly stated that NS is metaphysical and hence not testable. Either way Popper says NS cannot be scientifically tested.
“The claim that it [natural selection] completely explains evolution is of course a bold claim, and very far from being established.”
“The Mendelian underpinning of modern Darwinism has been well tested…”
“However, Darwin’s own most important contribution to the theory of evolution, his theory of natural selection, is difficult to test.”
“The fact that the theory of natural selection is difficult to test has led some people, anti-Darwinists and even some great Darwinists, to claim that it is a tautology.”
“I mention this problem because I too belong among the culprits”
“I have in the past described the theory as “almost tautological”, and I have tried to explain how the theory of natural selection could be untestable (as is a tautology) and yet of great scientific interest. My solution was that the doctrine of natural selection is a most successful metaphysical research programme.”
“I still believe that natural selection works this way as a research programme. Nevertheless, I have changed my mind about the testability and logical status of the theory of natural selection; and I am glad to have an opportunity to make a recantation.”
Popper may be recanting his belief that NS is a tautology, but he directly states, multiple times, that NS is metaphysical, which is also not empirically testable.
As to the claim that NS is a tautology; that is true or false regardless of what Popper has to say about it. The claim will stand or fall on philosophical grounds alone, not on what any alleged authority has said on the matter.
Only if I know it is a misquote. Thus far, you haven’t demonstrated that it is.
Does he? I haven’t seen that he does. You quote him continuing to describe it as a “research programme,” but not “metaphysical.” That adjective was dropped. Furthermore, you quote him as acknowledging that he changed his mind about its testability and logical status. He didn’t think it was testable before. Ergo, he must think it’s testable now. According to you:
So, if Popper now acknowledges that it’s testable, then he must not also think that it’s metaphysical.
If that’s true, it’s poorly placed sarcasm because the testability of natural selection is simply beyond question.
“Thus far, you haven’t demonstrated that it is [a misquote].”
I simply point out the illogic of your statement that I have a problem with Pigliucci, and not you.
Asserting that things are “simply beyond question” only hinders science, progress, and our ability to make sense of our world.
Both our interpretations of Popper are evidence based, but which interpretation better explains all the evidence?
You say: “He [Karl Popper] didn’t think it [natural selection] was testable before. Ergo, he must think it’s testable now.”
But Popper didn’t say NS isn’t testable. He repeatedly says that it’s difficult to test. Now if he changed his mind that NS is difficult to test does that mean he now thinks it’s impossible to test, or that it’s testable? Popper is ambiguous, and it’s my charge that his ambiguity facilitated sarcasm. Yet you don’t even acknowledge the ambiguity, but jump directly to your conclusion without recognizing that there are other possibilities. Your interpretation is not the only possibility as you would lead your readers to believe.
You must, then, prove that your interpretation is not only possible, but that it’s exclusive. In other words, you have to prove he is not being sarcastic as I have demonstrated. Your only remaining argument is that Popper drops the adjective “metaphysical”. Yet Popper maintains that his belief has not changed. His words “My solution was…” and “I still believe…” show that Popper continues to believe what he always believed, that NS “was” a metaphysical research program and “still…works this way”.
“My solution was that the doctrine of natural selection is a most successful metaphysical research programme…I still believe that natural selection works this way as a research programme.”
Evidence outside the text backs the evidence within the text. Popper called NS untestable in 1974 and “recanted” in 1976. Yet in 1982 he maintains “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.” (Unended Quest p168). This quote comes from a text revised 3 times over a period of eight years on 1976, 1978, and 1982. What Popper said before his “recantation” he continues to say after.
Ultimately, the problem I see you have with interpreting Popper’s words as sarcasm is that you can’t see how someone that is as intelligent as Popper could say something so obviously untrue (from your perspective). After all, whether we call NS a tautology, or untestable, or whatever, it still explains a heck of a lot of stuff in nature so all these claims are just word games played by those who want to knock down evolution.
What you do not see is that NS can be true, it just can’t explain the origin of species or life. NS appears to explain a lot. But NS can only explain within the boundaries of its assumptions. Since the existence of life is a premise of NS, NS can’t be used as an independent explanation for the existence of life. So then, just as Popper claims, NS is a successful research program given its metaphysical assumptions. All science, all theories, all things are based on certain assumptions. An explanation can confirm only within its assumptions, it cannot confirm the assumptions upon which it is based. Materialists have faith that there is no metaphysical cause for matter hence it is a necessary conclusion that all matter organized according to the laws of nature in some way. Materialists have made the error of thinking science is its own explanation, which is a logical contradiction. Science is a mode of investigation that excludes metaphysical causes a priori; it can’t prove its own premise. All creationists want is that evolutionists admit their metaphysical assumptions and stop calling their beliefs science.
And I simply point out why my statement was not illogical.
He implied it by saying that it was metaphysical.
Something that is difficult to test is, necessarily, possible to test - and by your own words, it’s a contradiction for something to be both metaphysical and testable. Since he states that it is testable, he must be denying that it is metaphysical.
I don’t find him ambiguous here.
I believe I’ve done that.
Or he means that he still believes that natural selection is still of great scientific interest and a great research program - but without being metaphysical. That’s most consistent with his actual words and doesn’t ad in words.
If that’s the case, then as I said before it’s unfortunate because it’s factually incorrect.
Only creationists and people who really don’t know anything about evolution expect evolution to have anything to say about the origin of life. As to the origin of new species, that’s been observed in both the field and the laboratory - and natural selection explains it just fine.
Some claim Popper recanted in 1976 yet in 1982 Popper maintains the very thing he is said to have recanted. Evidence from the text shows Popper’s “recant” to be a tongue and cheek response to his critics. Whatever people report on this subject from now on, they will be violating the ethics of full disclosure if they report that Popper recanted his claim that NS is untestable and neglect to report that he continued to believe that evolution is a “metaphysical research programme.”
You say, “Only creationists and people who really don’t know anything about evolution expect evolution to have anything to say about the origin of life.” Daniel C. Dennett in “Darwin’s Dangerous Idea” says that evolution is an algorithm that can turn chaos into order, and order into design. He concludes that a natural process by which chaos becomes design has far reaching ramification in all spheres of study overlapping biology, like a “universal acid” that burns everything it touches. Dennett shows that evolution is relevant to the origin of life, and I wouldn’t call him a creationist, or some one who doesn’t really know anything about evolution.
The deeper one’s knowledge of evolution the better one sees its inability to explain the origin of species. Whether this is because NS is a tautology and therefore has no power to explain, or it is because NS has no power to explain and is therefore a tautology, I haven’t yet figured out. Whatever we label NS, it cannot explain a straight line in development from a single cell to you or me.
We can, of course, debate the tautological status of NS ourselves, without making calls to authority. That is, unless you think NS taboo and you think it shouldn’t be questioned (Though I find questioning my assumptions to be very enlightening.)
To start, you keep making the claim that NS is observed, which is a fact irrelevant to the tautological status of NS.
“As to the origin of new species, that’s been observed in both the field and the laboratory - and natural selection explains it just fine.”
No one says NS has not been observed. Tautologies can be observed and NS is an observed tautology. “All naked people are not wearing clothes” is a tautology that can be observed “in both the field and the laboratory”. Just because something is observed doesn’t mean it’s not a tautology. Explaining why there are naked people in the field and laboratory is distinct from observing that they are there. If one offers the definition of an occurrence as the cause for that occurrence one offers a tautological explanation. Tautologies can’t be used as explanations because they attempt to use the observation of something as the explanation for that same thing. In short, tautological explanations confuse effects for causes by stating an effect is its own cause.
(BTW- new species form via various modes of a process called “speciation” and nobody debates its occurrence. It just can’t lead from single celled organisms to the diversity and complexity of life around us today, since speciation results in a reproductively isolated genetic subset of the original species. The subset of the genetic information in a single celled organism is not a step toward the information in you or me. Speciation is empirical evidence that genetic information decreases in a population over time.)
In logic, a tautology is a statement that is always true in a truth table. No matter what is plugged into the variables on one side the result is always true on the other. Tautologies can’t be scientific explanations since they can’t be empirically tested for their validity. They are true simply by definition. Statements can be tautologies by their logical structure like, “All crows are black or not black”. The statement is logically expressed “either X or not X”, and is always true no matter what we use to replace X. Statements are also tautologies when they make recursive claims like, “All naked people are not wearing clothes”, and “If dogs could sweat they’d perspire.” The fact that NS can be stated as the tautology “survival of the fittest” is a clue that it is a tautology, though this is by no means the end of the evidence.
NS is always true since it “predicts” all levels of complexity. The increase, decrease, or stability in complexity of organisms in a population are all “predicted” by NS. For example, if beetles with wings outlive beetles without wings then the beetles with wings are more fit because their wings allow them to travel further, and search for mates and food more easily. If beetles without wings outlive those with wings because on a particular island the wind blows flying beetles into the sea, then the beetles without wings are more fit. NS is a tautology because it “predicts” that organisms will survive that have traits that help them survive.
Your confusion arises in that it seems quite obvious to you that NS can explain the change in the average beak size in a finch population on the Galapagos after a drought, for example. But NS does not explain the change in beak size; it is the observation of the change in beak size. NS is simply the label we give for the death of a portion of a population that leads to a shift in the proportion of traits in that population. NS is an empirical observation that organisms that don’t die replenish the population. NS becomes recursive when we try to use it as an explanation for the same observation. We can’t make NS into its own explanation. If we start with the assumption that beaks of various sizes exist, and then we remove most small beaks (this is natural selection), we are of course left with bigger beaks on average. The cause of the big beaks is not that we removed small beaks, but that we started with big beaks as a premise. Since big beaks exist, then if they don’t cease to exist, they will continue to exist. The observation that something that exists has not ceased to exist does not explain why it exists in the first place. NS is a tautology because it restates its premise as its conclusion.
So NS is true (after all, tautologies are always true), it does occur “in both the field and the laboratory” as you said. You attack a straw man when you say it’s observed because no one, not even creationists, say that it’s not observed. Traits in living populations have been observed to change in proportion within the population. Some animals do die while others do live. The living, of course, replenish the population with their genes, and the dead do not. This is not an explanation of the source of life sustaining genetic info, but simply the observation that there is life sustaining genetic info. All parties agree that life sustaining genetic info will spread thru a population if it is present. The debate is over whether life sustaining genetic info spontaneously occurs in nature. But really there’s no debate because this has never been observed in either the field or the laboratory. Anti-evolutionists are simply trying to convince evolutionists that something that is not observed, but is deduced from a set of beliefs, cannot be a scientific fact. As soon as the formation of new genetic information is empirically observed the attempts will end, as there is no empirical evidence anti-evolutionists (including biblical creationists) reject. Since information has thru history been confirmed to be the product of the human mind alone, the best available theory says that whatever produced genetic information has a thinking and reasoning capacity similar to, but greater than, our own.
(There is one way evolution could be the origin of species. Devolution.)
(There is one way that NS is not a tautology. Inversion. NS explains the specific reason an organism didn’t die, not the reason it’s alive in the first place. But not really, NS is the observation that it happened)
Actually, Popper made the comment, “I have come to the conclusion that Darwinism is not a testable scientific theory.” in his 1974 autobiography (it was reprinted in 1982). That was what he was recanting in 1978.
In the 1978 letter Popper said, “My solution was (past tense)…” and “…I have changed my mind (present tense)…”
Popper does not find the theory of evolution difficult to prove, “The Mendelian underpinning of modern Darwinism has been well tested, and so has the theory of evolution which says that all terrestrial life has evolved from a few primitive unicellular organisms, possibly even from one single organism.” He only finds natural selection, “…difficult to test…”
It was that difficulty in testability that lead Popper to mistakenly label natural selection as metaphysical. “The fact that the theory of natural selection is difficult to test has led some people…to claim that it is a tautology.” and, “I mention this problem because I too belong among the culprits.”
So, apparently, is Stevedoetsch.
Popper recanted. How about you?
Since information has thru history been confirmed to be the product of the human mind alone, the best available theory says that whatever produced genetic information has a thinking and reasoning capacity similar to, but greater than, our own.
Given that “the best available theory” throughout history in the absence of satisfactory evidence was attributed to an intentional designer, is certainly a product of the human mind, I certainly wouldn’t put this little issue with natural selection out of league with such a blatant historical trend. Of all the best available theories that could exist, why be so eager to accept one with such a dubious track record whose best criteria for adoption is in the absence of knowledge of competing theories, rather than in the strength of support for its own position?
Kafir,
You are braver than I, tackling that paragraph. In my dictionairy, information = “Knowledge of specific events or situations that has been gathered or received by communication; intelligence or news.”
How about the “Theory of Devolution?” How does that work? Is that the theory that the original single cell organism was the “Crown of Creation” and what has happened since then is the degeneration of that perfect form? Is that one of those L Ron Hubbard stories?