On the Origin of Life and Falsifiability

It was considered perfectly reasonable to hypothesise the existence of planets outside our solar system before their existence was verified, but as we could never conceivably positively establish their absence from all stars in all galaxies, the hypothesis wasn't falsifiable.

Panspermia relies on the hypothesis that there is (or has been) life elsewhere in the universe. That's hypothetically verifiable, but not falsifiable. For me, that's absolutely no reason to exclude Panspermia from science. Of course it's a scientific hypothesis, although it's not actually an OOL one, of course.

The strange thing about your post is that the hypotheses you're suggesting aren't falsifiable actually are. For a start, the general hypothesis of the origin of life being on earth would have been falsified by the discovery that the planet was too young or that it was frozen for the first 4 billion years, or that it had been subject to a massive recent impact that would have sterilized it etc. etc. The fact that it's still looking O.K. for OOL on earth is a bit like the fact that we haven't observed "planets moving in squares", as Ruse puts it in the example you quote. And the general hypothesis being falsifiable in its nature means that all specific ones are.

Beyond that, some of the objections you list for "RNA" world and "Metabolism first" could conceivably be confirmed, which would be falsification. It's always hypothetical. I'd give them a better chance than observing planets moving in squares to falsify Kepler, wouldn't you?!

Usually, wrongly. Although a general hypothesis of intelligent design isn't falsifiable, neither are the planets or life elsewhere hypotheses I mentioned above. It could conceivably be verified. But many specific intelligent design hypotheses could be regarded as falsifiable, as you know. The standard YEC model is an obvious example that can and has been reasonably falsified.

I've not been around for a while, and haven't read the thread, so what I'm saying may well have already been said. Firstly, Popper's falsifiability notion can easily be questioned as in the examples I've given. Secondly, the OOL hypotheses you've discussed would be regarded as falsifiable anyway. Thirdly, I'm sure there are specific Panspermia hypotheses that are falsifiable, although it's difficult to think of a falsification of the general proposition. That, however, doesn't make it unscientific, just possibly un-Popperific, and who cares?

Cheers.

That it wasn't Popperian was my point. But it was, demonstrably, a damned good scientific induction.

You mean "Popperian" hypothesis, or "properly constructed" as you put it. I might have been wrong about general panspermia being unfalsifiable. When initially proposed, it could have been falsified if it could have been demonstrated that no organism could possibly survive in space. As that doesn't appear to be the case, we could say that the general idea has passed a falsification test.

Hypotheses don't become any less Popperian if possible falsifications also falsify other hypotheses. Think of your own chosen example from Ruse of "planets moving in squares". I don't know how many hypotheses that would falsify, but we could probably give the whole set an umbrella description like "cosmology"!

It's certainly Popperian. To add to the things I've already mentioned that would falsify it, future experimentation could establish that RNA is definitely too unstable to support even the simplest life forms on its own. Future experimentation could also confirm an alternative hypothesis beyond all reasonable doubt.

Not really, because their standard model is meant to be testable. The earth should appear 6,500 yrs. old and that should fit the data. That differs from other YEC models, particularly my favourite, the Omphalist version. That's the perfect example of an untestable, unfalsifiable model, because any and all data will fit.

The problem arises if someone implies that the hypothesis that the moon is made of cheese (Popperian) is inherently more scientific than the hypothesis that there are planets outside this solar system. The thing about the planets hypothesis is that the only reason it could be described as unfalsifiable is practical, unlike the Omphalist idea, which is untestable by its nature.

They're definitely falsifiable.

Well, you're the big Popper fan. Does this mean that you consider Kepler's laws to be improperly constructed? When I suggested that RNA could have turned out to be far more unstable than it actually is and incapable of supporting life in any circumstances, was that hypothetical falsification less plausible than "planets moving in squares"?

There might be problems with that. Firstly, you seem to regard the hypothesis that a simple organism without complex radiation protection could be sufficiently protected in some meteorites to survive a transfer as being both falsifiable and falsified, because you're treating the opposite as a fact. Are you sure of this? Then there's the Fuca - Luca problem you've been discussing with others. However, whatever the value of your suggested falsification, lithopanspermia is a perfectly respectable scientific hypothesis that has already passed falsification tests (it could have transpired that all organisms would have been destroyed in space).

You certainly haven't seen a compelling, detailed falsification scenario for the hypothesis that life exists off this planet yet, but it doesn't stop you assuming it without testing, does it?

As you like the historical approach, this abstract actually claims to have falsified RNA world.

http://www.karger.com/Article/Abstract/346551

It's gracious of you to say so (it's rare to read a phrase like that on EvC!).

We could have a Popper thread, but then I personally don't like the idea of reading his science related stuff beyond short extracts.

I'm sure that you'd get participation if you wanted to start a thread on falsification, which is certainly a valuable concept, whether I'm enthralled by Popper or not.

Thanks for the O.P. anyway, and for an interesting discussion. Panspermia is definitely good science, anyway. I'd be surprised if it hadn't happened somewhere in the universe at some time, whether it's part of our own story or not.