First off, I’m not the one making the deduction; Darwin did.
As for the rest, natural selection, as proposed by Darwin, required those facts to be true in order to function. Thus, it is still the case that the conclusion can be falsified by showing any of the “facts” to be false. If variation does not exist, natural selection cannot function. If competition for resources does not exist, natural selection cannot function. If the variations which yield an advantage in such competition are not inheritable, then natural selection cannot function. The conclusion is entirely dependent on the premises in this case.
But, more than that, natural selection must also be the primary creative force; that is, the majority of observed diversity must be explainable through natural selection. Note, however, that it is not required for all structures / behaviors to be thus explainable. This is why other mechanisms have been proposed in the first place. Nature is complex, so one should not reasonably (in my opinion) expect that a “one theory fits all” approach would be successful in explaining the whole of biological diversity.
Except, as noted, the conclusion is dependent on the premises, and the premises themselves are falsifiable. So, of course, falsifiable statements can be generated from it. Much of Origin was spent in supporting the premises, as well as the syllogistic conclusion.
This might be true if natural selection had been proposed to be the mechanism for eovlution. It was not, of course. It was put forth as the primary mechanism, and it was acknowledged by darwin that it may well not account for each and every trait which an organism might possess. This is the same trap that Behe falls into: the assumption that natural selection is not the primary mechanism, but rather the singular mechanism of evolution.
Sexual selection was proposed by Darwin to explain those traits which seemingly do not provide a competitive advantage (and may, in fact, appear to provide a disdvantage) in the realm of survivability, but rather in the realm of reproduction. Even then, it is, perhaps, mistaken to detach sexual selection from natural selection, as in many cases, the sexually-selected traits act as visual indicators for the presence of those traits which were the product of natural selection. The peacock with the large tail still must be able to survive, no matter how showy his tail. And, the showy tail alerts potential mates to the fact that the male is, indeed, “all that, and a bag of chips”. In other words, “it ain’t all show, baby!”
Recall that it was earlier mentioned that natural selection is a statistical phenomenon. As such, singular instances of traits which seemingly defy explanation in the context of natural selection do not necessarily act as falsfiers to natural selection, just as an errant gas molecule does not falsify the Kinetic Theory of gasses. This is not equivalent to saying natural selection cannot be falsified, however.
Notice you used the word “difficulty”, not “impossibility”.
The theory doesn’t presuppose them, it incorporates them. If a theory is a model built up from observations, then evolution is a theory built in part from the observation that the fittest survive by competing successfully, etc. There is no presupposition involved.
Well it’s a real pickle if that is truly what I did, however I think you may have misunderstood me. I’ve been unable to get back to the boards for a couple of days, but given the excellent quality of the arguments provided here I have only a little to add, however I will hopefully defend my earlier position.
I submit that picking any of the three options above would be utterly reckless, because far better conclusions are available within the scope of my earlier argument.
Svinlesha, I am pretty sure I did show how evolution is falsifiable in our last thread. I say that because I provided a list of points for falsifying evolution. I referred to the remarkable similarity in the genetic matter of living beings, and the findings of the human genome project; the former supports common descent for the overwhelming majority of living beings, while the latter indicates that mankind is descended from more primitive ancestors. Both these items were predicted by evolution theory.
(By the way, I will mention both frequently, so I’ll issue the probably unnecessary reminder that evolution and natural selection are not the same thing; rather, natural selection is the method by which evolution occurs)
Now, I agree with you and Popper that any hypothesis that can explain all conceivable observations and data is not testable and not scientific. It is, quite simply, unfalsifiable and therefore impossible to verify or disprove, thus it is useless to scientific inquiry. A scientific hypothesis that holds water must rule out some possibilities the actuality of which would render the hypothesis false. This requirement is the very basis of Popperian falsifiability, as you well know. Note, however, that the falsifying possibilities can easily be entirely conceptual, i.e. not actual and not realizable because A) the theory is so good that there are no exceptions and B) the conditions observed and incorporated by the theory (in this case natural selection) are ubiquitous. That, by the way, is what, at the end of a very long day, I clumsily called the “irremediable immersive nature of the environment” – goodness only knows what I was thinking.
An example of falsifying evolution theory is to imagine data that could invalidate the theory. To repeat:
possibility 1. the human genome study shows no genetic material sufficiently similar to or apparently recycled from genes present in other animals (of course, recycled genetic material is exactly what the human genome shows)
possibility 2. the genetic record of different species does not show evidence of being interconnected and related (of course, in reality there is less genetic variation than there is similarity among the animal kingdom, and when you look at humans and chimpanzees the two are over 98% identical on a genetic level; this is best explained by the theory that we and the chimps share a common ancestor).
Further, even Darwin himself predicted on the basis of his theory of evolution the existence of “transitional fossils”. Such fossils were later found and dated, and they fit in with the predictions of evolution theory. The continued absence of such fossils, or the discovery of fossils that did not corroborate but rather contradicted evolutionary predictions (i.e. Australopithecines alive 70 million years ago), would have been more problematic. We have just provided falsification criteria, simple as that.
Another (deliberately simplistic) example I used was the hypothetical crocodile, the one with eyes and nostrils on its underside competing with its normally built fellows. Were natural selection not applicable to the environment of the crocodiles, there is no reason for such foolishly designed crocodiles not to exist right alongside normal crocodiles (and the same goes for other outrageously poorly adapted animals in general).
Such a mutant crocodile, however, would be unable to compete and would die out without reproducing, leaving little or no trace. Out of sight need not mean out of mind, to go back to the falsifiability of natural selection. Poor adapatation and inability to compete = extremely low chances of survival.
I think you were confused by two things. First, the fact that natural selection applies to every living being we know of (see Darwin’s Finch useful syllogistic summary earlier in this thread). Secondly, by the complexity of the systems involved.
How would you falsify the theory of gravitation? Well, since the theory predicts that the attractive force between two masses should be inversely proportional to the square of the distance between them, that’s easy. To test the theory you would take two objects with mass, such as the Earth and a watermelon, and run an experiment. If you can conceive of a way in which the theory’s prediction doesn’t match the experimental observation, you have successfully shown the theory of gravitation to be falsifiable (i.e., if you can imagine that the two objects will repel each other, or if the attraction is inversely proportional to the cube instead of square of the distance, etc., then you have shown the theory to be falsifiable).
But you can’t really run an experiment on an evolutionary scale. And, when it comes to making observations, complexity becomes much more significant when dealing with living beings in a natural system – that is why you have the impression that evolution and natural selection are tautological. They aren’t. As long as you can conceive of ways in which to falsify evolution and natural selection, they remain valid. The apparent tautology is just that, apparent.
Some observations may lead one to superficially contradicting conclusions, but what’s truly important is the totality of evidence, not our impressions based on hasty conclusions or superficial examination. Let’s take a simple example I touched on in the last discussion, that of primate hand morphology. Orangutans have hand architecture best suited to power-gripping and brachiation, while baboons have an improved grasp that includes quite firm pad-to-pad precision gripping. Although these two types of hand morphology are in fact quite different from each other, it is perfectly acceptable to claim that the current existence of both hand designs is the result of natural selection, of being selected for in each case. Of course, if we just consider hand structure and nothing else that claim makes no sense because we have two “opposite” hand designs, but if we factor in the habitat, lifestyle, and basic characteristics of orangutans and baboons a clearer picture emerges: baboons have adapted to terrestrial life and have a finer hand grip to manipulate their more problematic food (such as grasses, nuts, insects); orangutans are extremely large and still lead primarily arboreal lives, which means that their hand morphology meets the challenge of brachiating, climbing and suspension (strength, long digits, maximized palmar friction, etc. are necessary for a secure handhold, especially in a massive animal like the ornagutan).
But even that is not the whole picture, far from it. To address this topic properly would require considerably more detailed information about both baboons and orangutans specifically, and primates generally. That is what I mean when I refer to the levels of complexity involved, which I suspect you fell victim to.
The third thing I wanted to mention (in addition to the ubiquity of natural selection and the importance of recognizing complexities) is that sometimes a particular morphology serves no purpose, or no obvious purpose. Why are humans saddled with as superfluous and dangerous an organ as the appendix, which is utterly useless and can easily kill if it becomes inflamed? I know the human appendix (like the tailbone) is vestigial, but I’m not sure that matters for the purposes of this point. Does natural selection account for the appendix in modern humans in the way you claim that natural selection accounts (tautologically) for the features of living beings?
Our eyes are designed quite poorly, with the retina all the way at the back of the ocular structure and blood vessels and whatnot obstructing the channelled light. An erect posture has brought us considerable evolutionary advantage, but just look at how poorly our spinal columns fare compared to other vertebrates.
It’s entirely possible that some organism features make little sense (perhaps they did in the past) and may even select against an organism, but that doesn’t necessarily mean the organism has to die out. It simply has to compete effectively against other organisms in order to survive, and it can do so with a mixture of advantages and handicaps, provided that it competes effectively. Certain features may confer both advantages and disadvantages at the same time (e.g., erect posture and the fragile human back, or the human eye) and in that case an examination of the complexities involved will be absolutely necessary lest one go astray and perceive the situation as a paradox of sorts.
In short, too much philosophy of science can be hazardous!
That’s an easy one. Appendices that are too small are more likely to become blocked and infected.
Thus, both very large and very small appendices are evolutionary disadvantages. Presumably the appendix will eventually vanish, but for the moment it’s preserved by the difficulty of eliminating it in one blow, instead of a more gradual diminishing which is much easier in a probabilistic sense.
Theoretically, it’s also possible that the appendix could evolve some new function that would make it advantageous. It wouldn’t be the first time that a formerly useless feature became useful. Evolution can be good at recycling old traits in new and different ways.
A truly amazing thread with some amazing analysis.
As soon as I saw the “Bombardier Beetle” question, I thought to myself, Brad you’re a Young Earth Creationist aren’t you? Well, maybe he is, I don’t know, but that little bug gets a lot of press coverage on Creationist web pages.
Think about this question Brad. Lets just suppose the Bombardier Beetle didn’t evolve, that in fact it was designed by a creator. Don’t you find it strange that it was designed with an apparatus to chemically burn to death would be predators? It seems to conflict with the Bible account where all creatures were created perfectly and lived harmoniously together in Eden eating the green vegetation. The lion lies with the lamb? Subsequently, if your answer is it evolved after the fall of man (sin enters) then it really evolved rapidly…more rapidly than most Darwinists would envision.
OPEN YOUR EYES PEOPLE! THE TRUTH IS ALL AROUND YOU!!! OK look. evolution is seen everywhere! here’s an example. Before England’s industrial revolution, a certain type of tree was white. During the revolution, the trees turned gray. After several generations, the moths that camoflauged themselves on the trees also turned gray. Then the cleanup act (or whatever it was called) occured in the 1960s. Soon the trees became white again and “voila!” So did the moths. Ive told a few christians this and they say the moths adapted due to natural causes. Well guess what. A bunch odf those "adaptations due to natural causes add up to a brand new species!
Thank you for your post. If you read my cite, it implies that the 1919 expeditions observed Mercury. The other cite says that the Eddington expedition, at least observed the stars. They could also have observed Mercury (which would be easier to see during an eclipse) but Mercury might not even have been visible at the time. So, I stand corrected, not having the time to check this out further.
The physicists who counted (whose ideas survived) did buy into relativity early. I wonder about older, more hidebound physicists. I think it would be utterly astonishing if they dropped lifelong beliefs that quickly. Science indeed adapts, as we both agree, but I would be surprised if it adapted quite that quickly.
The importance of the 1919 expedition was that it made Einstein’s theory publicly known. I thought it was Mercury, it was actually the stars, but perhaps the real reason was that Eddington was a very famous astronomer. That impressed the general public, just to be clear, not the scientific community.
Thank you all for your responses to my question. I received way more info than I will process in weeks.with the limited time i can spend here. I will read all your responses and maybe come back with other questions.
But I do have a job that demands most my time and can only spend short periods of time posting threads.
This is a pet peeve ignorance of mine. Just because you don’t understand the appendix doesn’t make it useless.
The appendix is a mass of highly vascularized lymph tissue. It’s situation in the intestines suggests to some that it functions as an early warning/sampling for foodborne antigens. Apparently it is important in early development as well. See Scientific American
Well, I must admit, your argument here has me in a bit of a muddle. I feel certain that it doesn’t hold water, but I can’t really put my finger on why. I suspect it has something to do with a combination of logical error – namely “denial of the antecedent” – combined with a fundamental misunderstanding of the general thrust of Popper’s thought.
Let’s begin with the last point first. A quick review of Popper’s reasoning reveals quite clearly that his criterion requires the deduction of potentially falsifiable observation statements from a given hypothesis, in order for that hypothesis to be classified as “scientific”:
or, perhaps more succinctly:
Yet, here you are, arguing that the falsifiability of the theory of natural selection is not based on it’s ability to generate testable observation statements, but rather on the logical relationship between it and its premises. Clearly, something is awry.
I suspect a disconnect over the way in which we are using the word “falsifiable.” It is true that, as a matter of logic, a sound argument that is based on true premises, and makes valid inferences, always leads to a true conclusion. But this does not necessarily imply that an argument based on false premises automatically leads to a false conclusion, as you seem to be claiming above. This fallacy in logical reasoning, “denial of the antecedent,” runs as follows: A implies B, A is false, therefore B is false. You are implying that if we falsify one of the premises in Darwin’s syllogism, we automatically falsify his conclusion. This is not necessarily the case. It’s a variation of the non causa pro causa fallacy, in which “something is identified as the cause of an event, but it has not actually been shown to be the cause.”
Perhaps a demonstration or two can help clarify my meaning.
Or, consider the following counter-example:
Hypothesis: higher rates of cigarette smoking cause a higher incidence of cancer among Swedish women.
Premise 1: Cigarette smoking causes cancer.
Premise 2: In Sweden, more women than men smoke cigarettes.
Logical deduction: A higher proportion of Swedish women than Swedish men will contract cancer.
Hopefully you will note that even though both of my premises are true (and falsifiable), they in no way guarantee the truth (or falsifiability) of my conclusion. In fact, in order to find out whether or not my conclusion is correct, I must test (i.e., attempt to falsify) it. I cannot merely go around telling people, “You see! My premises are correct and falsifiable: therefore, my conclusion is falsifiable! In fact, we don’t even need to test the conclusion: we can merely test the premises! Should they survive rigorous attempts at falsification, then the conclusion is probably true as well!”
In addition, even if it were to turn out that one of my premises is incorrect, that does not necessarily imply that my conclusion is false: for example, even if premise (2) is false, it is entirely possible that more women than men die of cancer in Sweden.
In this counter-example, luckily, the logical deduction is also readily falsifiable, which simplifies matters. With evolutionary theory, on the other hand, the deduction Darwin presents to us – while imminently logical and scientific – does not easily yield up falsifiable observation statements. Pursuant to this observation I would like to reiterate point 3 from Popper citation, above:
Every “good” scientific theory is a prohibition: it forbids certain things to happen. The more a theory forbids, the better it is.
Perhaps, rather than chasing our tails in these circles, you could present me with some things that your proposed mechanisms for evolution forbid. cajela has already given me one good example – “Bacteria kept in an antiobiotic-rich medium will evolve resistance” – but I fear that I need more. A strong, versatile theory should present us with a multitude of falsifiable observation statements, according to Popper, in order to be considered scientific. Voyager:
Yes, I can see how that page would confuse you. Abe:
I think the part of the problem with finding easily refutable predictions of Evolutionary Theory is that it’s inherently probabalistic. Statistical sciences have a very difficult time producing precise predictions without working with an astronomical number of test units.
Fascinating, thank you for the update. I was indeed utterly ignorant of this information, though it seems there is still a lot we don’t know about this tricky little organ. Not to hijack further, but is there an appreciable difference in immune functions among adults with and without the appendix? And what about in children, when the appendix seems to be more active?
[appendix hijack]No sweat on the update(like I say it’s a peeve of mine) but I don’t want to come off as an expert. I’ve studied anatomy/physiology for a couple of years is all. I don’t think a lot of research has been focused yet on long term complications. There seems to be an increased risk of Crohn’s Disease for those having appendectomies Link
As it is active lymph tissue it’s removal directly lowers immune resources regardless. People can live without their axillary lymph nodes (eg after masectomy) but we don’t call them vestigial organs. I honestly don’t comprehend why they were ever considered useless.[/appendix hijack]
I am of two minds as to how to respond to your last reply – the short way, or the long way. Perhaps I should just start with a couple of general observations, and see where they lead me.
I am beginning to suspect that you are missing the real gist of my stance in this discussion. I get this feeling because you continually post arguments that undercut your own position, and support mine – and yet, at the same time, you seem blind to this fact even when I point it out to you. Some of your arguments are a bit specious (especially in this last post), while others provide detailed (and in my opinion, valid) explications for why natural selection is difficult (perhaps impossible) to falsify.
I suspect in part this misunderstanding arises because you are confusing my critique of the falsification criterion with a critique of the theory of evolution, probably because these two issues are so tightly connected in your mind. As a result, I often feel compelled after reading one of your posts to defend myself from the false charge that I am somehow strongly critical of the scientific status of the theory of evolution, when, in fact, I am not. Rather, I am attempting to use evolutionary theory to demonstrate the weaknesses of Popper’s falsification criterion as demarcation between “the statements, or systems of statements, of the empirical sciences, and all other statements” (Popper, Conjectures and Refutations, 39-40). Therefore, every time you point out that significant obstacles exist to falsifying the theory, you are arguing my case for me. I am well aware that, though difficult (perhaps impossible) to falsify, evolution is a logical, elegant, empirically-based, sophisticated, probably-true explanation of the diversity we find in nature. In fact, for me, it is precisely the compelling strength of the theory (for which you argue so eloquently), combined with the difficulties it presents in terms of falsification (for which you also argue quite eloquently), that highlight the shortcomings in Popper’s thesis.
Now, for a few point-to-point rebuttals:
Yes, naturally, I am not 100% convinced that my arguments hold water. If I were, I doubt I would be wasting my time with this discussion. Must we mark words like this?
Very well, substitute the word “incorporates” for the word “presupposes.”
As you point out, the theory incorporates factors like “chance,” “competition,” “survival of the fittest,” and the “irremediably immersive nature of the environment” which, on the one hand, allow us to describe all possible observable outcomes of an assumed evolutionary process in terms of the theory, but, on the other hand, make it impossible to derive specific falsifiable observation statements.
The assertion, although perhaps dogmatically worded, nevertheless holds, and you have not yet rebutted it.
”Hello? Hello?”
:tap-tap-tap:
“Is this thing on?”
Wrong. You are agreeing with Popper. I am disagreeing with you and with Popper. I am arguing that some untestable hypotheses (that explain all conceivable observations) are nevertheless scientific, and suggesting that the very real difficulties bedeviling tests of natural selection support my assertion.
May I suggest that, if you promote this particular (strict) interpretation of the falsification criterion, you will run into very serious difficulties finding any falsifiable (and therefore non-scientific) theory?
We could use the argument you promote above, for example, to extend the mantle of scientificity to both astrology and psychoanalysis. In both cases, we can claim that, because “A) the theory is so good that there are no exceptions and B) the conditions observed and incorporated by the theory (in this case astrology, or psychoanalysis) are ubiquitous,” they must be granted the status of falsifiability and therefore are sciences. We can then locate absurd “possibilities” that might conceivably falsify them, and claim that since we have not ever observed these possibilities, we have two, thus far “unfalsified,” scientific theories to hand.
Astrologers consult the stars and predict that frogs will not rain down upon Prague on the day of August 23, 2003. This prediction is clearly falsifiable; frogs in Prague, tomorrow, and astrology will be falsified. No frogs, on the other hand, and astrology will have survived an “entirely conceptual” falsification test, thus demonstrating its status as a science.
Let us keep an eye on the newspapers tomorrow and see what happens.
In his analysis of Schreber, Freud postulates the existence of an etiological link between homosexuality and paranoia. Specifically, he suggests that paranoid fantasies of persecution are a defense against powerful homosexual longings which the paranoid unconsciously experiences as threatening. To defend himself from consciously recognizing these repressed urges, he executes a two-step defensive maneuver:
Basic situation: I love him.
Defense 1 (reaction formation): I don’t love him; I hate him.
If this defense is not sufficiently effective, a second one is employed:
Defense 2 (projection): I don’t hate him; he hates me.
This combination of defenses, reaction formation + projection, are the classical signs of a paranoid personality. The delusions of persecution always begin their development with a focus on one person (the rejected love-object, now experienced as threatening other) but gradually spread out, in extreme/psychotic cases, to include the entire field of object relationships.
Now, this thesis is conceivably quite falsifiable. We have but to locate a single paranoid person who does not display any signs of homosexuality whatsoever. In fact, Freud even published a short paper which contained an account of a woman who, at first glance, appeared to falsify his theory (A Case of Paranoia Running Counter to the Psychoanalytic Theory of Disease, 1915). However, in that case, he uncovered the “homosexual attachment” later in the analysis, which led him to conclude that his hypothesis was still viable.
Admittedly, human relationships are extremely complex, which makes this particular thesis very hard to falsify, especially outside the clinical space. Indeed, as you note yourself, “* when it comes to making observations, complexity becomes much more significant when dealing with living beings in a natural system…*” Since it is so difficult to clinically identify denied homosexual urges, I suggest the following experiment: raise a person in such a way that they never have contact with a member of the same sex. We can imagine a situation, for example, in which a person (let us say, a man) is raised exclusively in the presence of women; he therefore never has the opportunity to form a same-sex relationship. Our theory would predict that a man raised under such circumstances would never develop paranoia. One counter-example would falsify the theory. I realize, of course, that this example may be “entirely conceptual,” “not actual and realizable;” but as you note, such conceptual falsifications are allowed via Popper’s falsification criterion.
I hope the two examples above demonstrate why your argument puts you on epistemological thin ice. To my eye, the interpretation of the falsification criterion you propose above invokes a kind of “reductio ad absurdum” quality; in order to assert the falsifiability of natural selection, you reduce the meaning of the criterion to the point that almost any statement, or series of statements, can be classified as scientific. Larry Laudin sums up a rebuttal to this particular version of the criterion quite nicely in his The Demise of the Demarcation Problem:
Conversely, we can look at good examples of falsifiable observation statements derived from evolutionary theory. As you know, I’ve already conceded that the pathways posited by the theory, and derived from the fossil record, are falsifiable, on the basis of the arguments presented by tomndebb and cajela. Why is that? Because these hypothetical pathways rule out an vast number of easily observable phenomena, such as the existence of hominid fossils in pre-Cambrian strata, and so forth. If you follow Popper’s reasoning, you will note that it is precisely a theory’s ability to rule out large numbers of such potential phenomena that presages its status as scientific. Neither is there anything “conceptual,” or “not realizable” about these predictions; they state flatly that we will not find hominid fossils in pre-Cambrian strata; if we do so, or if we find any of an almost limitless number of other precluded fossils there, then the theory will be falsified.
This has gotten long, and I need to round off. Before I go, let me present to you some of the claims you posted in your last reply that, paradoxically, argue against the falsifiability of natural selection:
All of these arguments demonstrate the difficulty (perhaps impossibility) inherent in falsifying the theory of natural selection.
Finally, this:
You mean, for example, too much Popper?
(I know that you have addressed a raft of other issues in your last post; I’ll try to finish off my reply to them at the earliest opportunity.)
