Would this principle be exemplified by certain considerations of the Fermi paradox, where if we were to find a fossil of a multi-cellular organism on Mars, it would confirm the doom of humanity?
Brilliantly set out here.
Summary: Where is everybody? Answer: There’s actually no one out there due to some cataclysmic event that prevents all or nearly all life from evolving to the advanced level necessary to explore the universe. The great filter.
Our only chance is that we’re the special ones who have passed the great filter, and can continue evolving - e.g. imagine the jump to eukaryotic cells was a one in a billion event, the great filter we passed through and no one else did.
Hence, if we were to find fossilised life on Mars it would be a disaster, as it would indicate that life is extremely common in the universe, thus removing a number of great filter candidate events from our history.
I know a proofreader who hates to find a single error. If she finds zero, that’s acceptable. If she finds two, that’s fine also. But finding one makes her think she missed a second.
That’s pretty much nonsense. Or at least your explanation of it is.
It assumes the great filter, if it exists, must be in our past. The fact we’re far, far short of “exploring the universe” today says the filter may be alive and well; just lurking farther in our future.
Arguably it’s out there and has killed off countless other civilzations in the past. And it’ll get us in turn too. Just not yet. Absence of evidence is (at best) weak evidence of absence when we’re dealing with a very finite sample size.
I’m not saying such filters exist or don’t. I’m saying we can say almost nothing about the question. Discovering, or not discovering, Martian fossils would change almost nothing about our knowledge vis-à-vis hypothetical great filters.
In proofing my own papers, I have often observed that there must be infinitely many errors. Proof: No matter how many I find there’s always at least one more.
But to get back to the OP, I concur that it really is Baysian reasoning. Finding one easily when you a priori didn’t expect to find one, at least not easily, changes your expectation of how many there are to find.
And of course, there’s the classic uni prank of getting three pigs, painting the numbers “1”, “2”, and “4” on their sides, and letting them loose in a building. The pigs quickly get caught, but everyone starts looking high and low for where #3 got to.
It doesn’t say that. Why do you say it must be in the future just because we’ve yet to evolve into a type III civilisation?
This makes no sense to me, so I’d be interested to see what I might be missing. If we found a Martian fossil (and for the sake of argument let’s exclude any panspermia hypothesis, the lifeform evolved separately on Mars), then this tells us plenty about candidates for the great filter. It says that the evolutionary process up to that point cannot be regarded as special, or a freak occurence - a great filter event, as we’re seeing it right next door in the vastness of the universe.
Hence the guys point - if we found a complex multi-cellular fossil on Mars, then the great filter is almost certainly ahead of us.
Well, I think most posters understand what I am getting at and might agree that there’s some logic to this “principle.” And the folks pointing out Bayesian theory seem to be barking up the right tree.
I myself have used various versions of the Copernican principle in conversations, and as pointed out above, that sounds congruent. I was hoping for an easy, understandable formulation and a specific name I could use as a shorthand reference, however.
I thought I’d run into this in an old Stephen Jay Gould essay, Dinosaur in a Haystack. But I dug my copy up and skimmed the essay, and I seem to have confused this with the Signor-Lipps effect, which Gould discusses at length.