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Comment by EGreg | Hacker News Reader

Besides reproducibility, you also need to make testable predictions for it to be science. I wonder what would the testable predictions be for most evidence that all (or almost all?) evolution proceeds entirely by random mutation and natural selection. If this isn't true then a lot of the stuff in evolutionary psychology and other "just so" explanations may be completely unscientific. Exemplified by crap like this: https://www.theguardian.com/science/2007/aug/25/genderissues

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If you are looking for solid evidence that current living things originated by common descent and speciation through evolution by natural selection, that evidence is abundant.[1] Some of the evidence backing up what is called "evolutionary psychology"[2] is much more debated, and much more problematic, and other psychologists are quick to criticize many evolutionary psychology publications.[3]

[1] http://www.talkorigins.org/faqs/comdesc/

[2] http://www.cep.ucsb.edu/primer.html

[3] http://www.larspenke.eu/en/publications.html

Those are two different things: the theory of common descent has a lot of evidence in its favor. On the other hand, the claim that all features observed today have been the result solely of random mutation and natural selection, is rather untested. It doesn't make many testable predictions. The mathematical issues with the theory (wherein, on its own terms, the chances are infinitesimal of it being true) are rarely addressed in mathematical terms, instead most responses are of the type "well X1 feature might have helped Y animal survive and reproduce better until it led to X2 feature". If you look at tons of published literature that mentions evolutionary explanations, it is all "just-so" stories which already assume the theory is true.

I am talking about the following criterion in order to qualify as a real scientifically tested theory:

http://www.stephenjaygould.org/ctrl/popper_falsification.htm...

According to this criterion, the theory that random mutation and natural selection alone produced all the genotypes we see is like Marxism and Freud's psychological theories. If we assume they are true, we can explain everything with just-so explanations. But that's not falsifiable, it doesn't make testable predictions. NOTE: this is different than saying all animals had common ancestors. It says we know how the changes happened that led to the current features. The fact is, we don't know. We barely have scratched the surface. We are still in stages comparable to the luminiferous ether theory in ohysics or humors in biology. I think in 100 years people will look at our theories of random mutation and natural selection (whether classical, punctuated equilibria etc) and consider us naive. And yet we have proponents like Dawkins yelling from the rooftops that "evolution is as proven as gravity". That's equivocating the word "evolution" with common descent. There is also a lot of pressure and political interest from demand for a naturalistic explanation, similarly to how there is demand from the religious camp for "the institute for creation research". It affects who gets research and who gets published. Science is a human endeavor and it is affected by political and organizational pressures just like everything else. But when something is testable and is being tested, it's obvious. Here nothing is obvious - even the math is dubious. These theories are just riding on the coattails of the theory of common descent because we don't have better naturalistic explanations at the moment. But just because a theory is the best we have doesn't mean it's true. Overstating it is, is more advocacy than science.

That hypothesis isn't falsifiable. We know "X effects Y" from experimental result. You're asking for proof that "X and only X effects Y", which is the same as asking for "There does not exist some X' that effects Y" where the set of X' is unbounded. No, that's not testable and doesn't need to be.

Just like we didn't need to know about the X' of Einstein's equations to know that the X gravity was the primary force holding you to the ground.

There very well may be an X' that effects observable biological features other than evolution, but that X' needs to be tested on an individual basis. So while it's productive to hypothesize an X' and test it, there's not much we can do to rule out all X' as a class.

So if you can't rule them out, your theory shouldn't postulate that they don't exist. It's one thing to do 100,000 experiments and have the results COMPLETELY predicted by Einstein's equations beforehand. It's quite another to invent just-so stories in terms of the theory itself after each observation!

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