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from the out-with-the-old-priors-and-in-with-the-new dept.
New Theory Concludes That the Origin of Life on Earth-Like Planets Is Likely:
Does the existence of life on Earth tell us anything about the probability of abiogenesis — the origin of life from inorganic substances — arising elsewhere? That's a question that has confounded scientists, and anyone else inclined to ponder it, for some time.
A widely accepted argument from Australian-born astrophysicist Brandon Carter argues that the selection effect of our own existence puts constraints on our observation. Since we had to find ourselves on a planet where abiogenesis occurred, then nothing can be inferred about the probability of life elsewhere based on this knowledge alone.
[...] However, a new paper by Daniel Whitmire, a retired astrophysicist who currently teaches mathematics at the U of A, is arguing that Carter used faulty logic. Though Carter's theory has become widely accepted, Whitmire argues that it suffers from what's known as "The Old Evidence Problem" in Bayesian Confirmation Theory, which is used to update a theory or hypothesis in light of new evidence.
[...] As he explains, "One could argue, like Carter, that I exist regardless of whether my conception was hard or easy, and so nothing can be inferred about whether my conception was hard or easy from my existence alone."
In this analogy, "hard" means contraception was used. "Easy" means no contraception was used. In each case, Whitmire assigns values to these propositions.
Whitmire continues, "However, my existence is old evidence and must be treated as such. When this is done the conclusion is that it is much more probable that my conception was easy. In the abiogenesis case of interest, it's the same thing. The existence of life on Earth is old evidence and just like in the conception analogy the probability that abiogenesis is easy is much more probable."
Journal Reference:
Daniel P. Whitmire. Abiogenesis: the Carter argument reconsidered [open], Int J Astrobio, 2022. DOI: 10.1017/S1473550422000350
(Score: 2, Interesting) by khallow on Wednesday October 05 2022, @11:26AM (5 children)
Sorry, that's broken. First, you can't "assign values". There's only two relevant values to that mutually exclusive conception example - one scenario is true and the other false. There is no room for assignment of probability values and neither scenario is at all changed by old evidence. In order to have the ability to assign values as he does, you implicitly have additional evidence. And well, the additional evidence is what is shaping the probabilities not the old evidence.
What's particularly bizarre about the paper is that the treatment of old evidence has traditionally been that it doesn't distinguish between hypotheses that are compatible with the old evidence - the very opposite of the stance he is taking here. For example, if you have alternative plausible theoretical explanations for Mercury's precession than General Relativity, then those are just as valid until you come up with new evidence. Assignment of probability values is futile because the old evidence doesn't distinguish between these rival theories.
(Score: 2) by bart9h on Wednesday October 05 2022, @05:06PM (4 children)
I haven't read TFA, but TFS smells like BS.
The best origin-of-life theory I have came across is on the book The Vital Question [wikipedia.org], by Nick Lane. I highly recommend it.
(Score: 2) by mcgrew on Wednesday October 05 2022, @06:59PM
I did read TFA, and it is also hand waving and calling an untestable hypothesis a "theory". It's no more valid than Pizzagate, except that Pizzagate was easy to debunk.
mcgrewbooks.com mcgrew.info nooze.org
(Score: 2) by Immerman on Wednesday October 05 2022, @08:24PM (2 children)
Does he offer any interesting insights? From the Wikipedia page it looks like he just makes some descriptions of how life works today, along with some references to the hydrothermal vent origin theory which was already going mainstream at least a decade or two before before publication.
Presumably he tied it together with a nice "I don't speak science" bow to become popular, but does he offer anything of interest to people who *do* speak science?
(Score: 2) by bart9h on Thursday October 06 2022, @08:10PM (1 child)
Yes, he does.
The book is not light on science. I had a hard time following it.
(Score: 2) by Immerman on Friday October 07 2022, @04:03AM
Cool