Let’s talk about Uncommon Descent for a moment. One of the recurring complaints we’ve been hearing from the evolution denialists there is this refrain that whenever a evolutionary explanation for a result gets reevaluated, it’s a sign that we “Darwinists” are somehow being dishonest and fitting any data to the theory of evolution. Evolution, therefore, isn’t falsifiable. For example, two posts, one from BarryA, the other from O’Leary (commenting on this ARN nonsense, wrongly suggesting that results that falsify evolutionary theory have been discovered – like the recent hypothesis the appendix has a function – and that we just ignore the problem.
In Edge, Behe talks about Ernst Mayr’s 1960’s prediction that on Darwinian grounds the search for homologous genes would be quite futile. Now Darwinists use homologous genes as evidence for the theory; after all the existence of such genes was predicted by the theory (after the fact).
What can you say about a theory that can just as easily predict “X” and the opposite of “X”?
I commend to our readers sections 19 and 20 of Popper’s Logic of Scientific Discovery, in which he discusses “conventionalist stratagems” to rescue a theory from falsification. Popper writes, “Whenever the ‘classical’ system of the day is threatened by the results of new experiments which might be interpreted as falsifications . . . the system will appear unshaken to the conventionalist.” Popper goes on to explain the stratagems the conventionalist will use to deal with the inconsistencies that have arisen between the predictions of the theory and the results of experiments:
Despite its name – which means “hanger on” – the human appendix works for a living, according to recent research (helping kill germs). [ed – note she didn’t even read it!]
As British physicist David Tyler notes, despite the claim of evolutionary biologists from Darwin to the present day that the appendix is junk left over from evolution, the appendix actually has a function – and the current crop of evolutionary biologists try hard to avoid acknowledging that they were wrong about that.
I think this warrants further discussion for two reasons. One is that it exposes, again, how the UD cranks just don’t get science. As someone who favors Popper’s view, I’m particularly pissed that the purveyors of the unfalsifiable would use him to promote their crankery. Second, there is often a problem in scientific communication that some people propose sloppy evolutionary speculations for findings that feeds these cranks ammo. First, let’s go over why the statements by our UD cranks are incorrect:
Let’s first address O’Leary’s claim that evolution predicts the appendix is worthless. Is this true? Of course not. First of all, the claim that she cites is a hypothesis, albeit a plausible one. Second, even if it is a correct hypothesis, the human appendix, compared to homologous ones found in other animals is still vestigial, as it has clearly lost functions found in other animals – such as cellulose digestion – and even if the bacterial replacement hypothesis were correct its function would still be redundant. This should be obvious because people with removed appendixes don’t fail to repopulate their intestinal flora after antibiotic treatment or GI illness. What O’Leary has done is make a fundamental error in the understanding of the word “vestigial” and conflated it with “non-functional”. Vestigial does not mean non-functional. Rather, a vestigial organ is one that is a footprint of an organ in another species, that has lost its original or primary function. In the linked PT essay, the comparison is made between the appendix and an ostrich’s wings. The ostrich doesn’t fly, its wings are vestigial, but that doesn’t mean they are without function.
Further, this is an historically incorrect view of the appendix, which people have been proposing functions for ever since Leonardo di Vinci, and many have been suggested long after Darwin. Evolutionary biologists didn’t say “evolution predicts no function for the appendix” all they’ve said is that it has lost its primary function and is therefore vestigial. Take for instance, this quote on Talk Origins from 1912’s The Story of Evolution.
“The vermiform appendage–in which some recent medical writers have vainly endeavoured to find a utility–is the shrunken remainder of a large and normal intestine of a remote ancestor. This interpretation of it would stand even if it were found to have a certain use in the human body. Vestigial organs are sometimes pressed into a secondary use when their original function has been lost.”
The Story of Evolution (1912), p. 264
This essay at Talk Origins really is wonderful, but I’ll just list the 4 fundamental points which shows just why O’Leary and David Tyler at ARN are complete fools:
- The human appendix may have bona fide functions, but this is currently controversial, undemonstrated in humans, and irrelevant as to whether the appendix is a true vestige or not.
- The appendix is a prime example of dysteleology (i.e. suboptimal structural design), a prediction of genetically gradual evolution. [Take that DI!]
- The appendix is a rudimentary tip of the caecum and is useless as a normal, cellulose-digesting caecum.
- Thus, the appendix is vestigial by both the evolutionary and non-evolutionary, typological definitions of vestigiality.
To sum up, O’Leary/ARN wrongly suggest that a hypothesis has been confirmed to be the function of the appendix, this is clearly a misunderstanding of the word “vestigial” to mean “without function”, and attacks an “Darwinist” argument that has never been made. I expect a retraction promptly. Ha!
Onto BarryA, who I believe is following up on O’Leary’s nonsensical post with a Popperian attack on “Darwinists”. First of all, what did Mayr say? (Never trust a cdesign proponentsist on a quote):
“Much that has been learned about gene physiology makes it evident that the search for homologous genes is quite futile except in very close relatives…”
It’s true he said this, and its true that he was completely and absolutely incorrect. This was a speculation made in 1960, long before the human genome project, and in the absence of the reams of data on homology and gene sequencing that suggests a great deal of homology between genes in even distant ancestors.
So, does one man’s opinion about what molecular evidence we might find then disprove the entire framework of biology when he’s proven incorrect? Of course not!
The mistake that is being made here is suggesting that just because we fit results into the overarching framework, the fact that more than one result can fit suggests the framework isn’t valuable. Nothing could be more absurd. If someone discovers something that conflicts with the current framework of molecular biology – for instance the original transfer of information in molecular biology that DNA is transcribed to RNA and then translated to protein – that doesn’t invalidate all of molecular biology. The discovery of reverse-transcriptases was a big surprise. Suddenly we found RNA could be used by viruses as a genome that would then be transcribed to DNA and inserted into a host genome, and then back into RNA again to assemble the viral genome. Should we toss out the previous framework? Don’t be absurd! You modify it to be consistent with the current data, because it still works, and is still correct, it just needs to be expanded to be more complete.
Another example from physics would of course be the move from Newtonian mechanics to relativistic mechanics. Are Netwonian mechanics invalidated by relativity? Of course not. They work great at non-relativistic speeds. It’s just the the Newtonian system is incomplete not wrong. A theory doesn’t have to predict everything to be useful, and finding new evidence that wasn’t predicted – like the apparent increasing mass of particles as they approach light speed – doesn’t invalidate the previous theory or all the data that went into it. For the DI cranks to suggest this is unscientific behavior shows what poor scientists they are. This is the kind of stuff we live for!
The theory of evolution is very robust. It tolerates many different kinds of findings without falsification, and none of the examples, or more correctly misunderstandings, provided by the cdesign proponentsists falsify the theory. These fundamental errors made by the cdesign proponentsists also clearly demonstrates that they just don’t get science. New data that changes our understanding of biology doesn’t invalidate all of biology. And extraordinary claims like “a magic man done it” require extraordinary proof. The fact that one evolutionary biologist, even a great one like Mayr, made an incorrect prediction isn’t evidence of anything but the intellectual dishonesty of these cranks. The proposal of a new hypothesis about a vestigial organ (which would still be vestigial if it were true or not) does not invalidate evolution. The fact that they think it does, is again, only proof of the scientific illiteracy of evolution’s critics.
Evolution is falsifiable. For instance, if we found out that every species on the planet has a completely unrelated genome, with no homology between close or distant relatives, and no sign of branching ancestry, the theory would be in trouble. The fact is that we find the opposite. We find high levels of homology that break down consistent with molecular clocks as you travel back in time to branching points with our distant ancestors, and this is incredibly consistent with fossil timescales. All the evidence points to common ancestors. Alternatively, if we found no relationship between the physiology and function of organs in closely-related living animals, the theory would be in trouble again. Consistent with evolutionary theory we find the opposite, with many mechanisms conserved even in evolutionarily distant species. A neuron in a squid, for instance, functions much the same as a neuron in a human. It’s why comparative medicine works. A human is not a mouse, but we have enough in common that we can learn a great deal about a drug, or a tissue, or a molecular signaling pathway by studying the mouse. Take the recent finding of reprogramming adult cells into pluripotent cells. Where was the work done to find the 4 genes? In mice! The same 4 genes could transform cells from both animals (or two really, as Thomson showed).
Finally, I said I would talk about some of the stupid evolutionary speculations made by people that give cranks like cdesign proponentsists ammo. I can think of no better example than the pathetic neo-Lamarckian nonsense of an evolutionary explanation for why boys like blue and girls like pink that we saw earlier this year. It was a failure of scientific speculation on multiple levels. Their view was fundamentally-flawed as a misunderstanding between biological and cultural phenomena. Further, their evolutionary explanation was absurd, and would not fit into any reasonable framework of selection. It’s just that kind of stupid crap that makes the cdesign proponentsists happy, because it’s scientists acting like idiots. Being cranks, they think stupidity on the part of scientists validates their stupidity. Let’s stop making it so easy for them, OK?