I've always found that saying dumb. It's basically stating that this is the null hypothesis, and you have to have p = 0.001 to convince me otherwise.
When dealing with complex questions of which we have but datapoints, the probability of scenario A vs B moves in a linear scale, not according to arbitrary requirements of "extraordinary evidence".
On our journey through life, most people develop a fairly good sense of prior probabilities and that manifests through excitement. Actual aliens? Exciting. People misinterpreting noisy information? Dull. Telephone game stories getting out of hand? Dull. People lying for clout? Dull. Prestigious people doing all of the above? Dull, dull, dull.
Equal-weighting an arbitrary list of options is a terrible prior distribution that does not tap anyone's knowledge of how the world works. Weighting by excitement, however, does exactly this. To convincingly prove aliens you need to convincingly disprove the dull alternatives. It's easy to imagine extraordinary evidence that could do this -- but I don't see any extraordinary evidence here. I see a bunch of ordinary evidence and people who want to believe.
It’s nonsensical to claim that to prove something you have to disprove alternate explanations. In an information environment where confirmable facts are scarse, you get the clearest vision by operating on probability. And on black-swan-tier questions the ’wisdom of the crowd’ is worthless - too much noise caused by nobody willing to advocate the black swan event, and too little prior events for the crowd to be able to calibrate itself beyond this.
Your way of dealing with complex questions is also arbitrary.
In today's economy of attention, grifters are very common and extraordinary claims like "I know for a fact that Aliens have made it to Earth and they have technologies beyond our current understanding of physics. Also there is a conspiracy to hide this fact." can rationally be ignored in the absence of irrefutable proof. At most it's entertaining to hear.
> When dealing with complex questions of which we have but datapoints, the probability of scenario A vs B moves in a linear scale, not according to arbitrary requirements of "extraordinary evidence".
That may be true, but I the case of interstellar travel, we have mountains of solid evidence to prove it's not possible (essentially all of physics for the last 100 years or so), and some vague claims with 0 evidence claiming it's actually happening. To convince us that all that physics is wrong you have to bring some extraordinary evidence, not claims that you heard someone knows someone who saw something.
Interstellar travel is possible even with the physics we know. A sub-light civilization could colonize the entirety of Milky Way in a million years or so.
The question is what the probability is for an intelligent species to evolve per solar system, and the more complex questions of how long they would survive etc. We only have a single datapoint (us) which only gives us the knowledge that intelligent life can evolve, but no direction whatsoever as to its probability.
I should say not feasible instead of not possible. And this million years number comes with some massive assumptions about societal stability, the possibility of mining resources from lifeless planets etc.
Notwithstanding that p-values precisely can't tell you about the relative probabilities of different events (they measure the probability of data under a given hypothesis, rather than in favor of a specific alternative), you have it precisely backwards. In this case, we have anomalous observations, but we have a current-best-understanding of the physical universe that makes us skeptical of supernatural claims (a bucket into which I include magic star hopping aliens that only allow us glimpses of them jetting around our atmosphere).
So either we have a strong prior that the data needs to overcome, or we have a sensible null position (e.g., UAPs are the result of natural phenomena or human technology - probably both) that would need to be overcome by strong evidence.
It's still worth getting more specific and learning more about the bucket of things that get lumped together into "UAP", but that doesn't change the fact that I think people are completely justified in dismissing all the alien BS.
When dealing with complex questions of which we have but datapoints, the probability of scenario A vs B moves in a linear scale, not according to arbitrary requirements of "extraordinary evidence".