Skeptic: “If it’s aliens, why haven’t they been trying to contact us” Post-hoc variation: “Because of the Prime Directive”
Skeptic: “If it’s a physical vehicle, why does it not obey the laws of physics” Post-hoc variation: “Because the aliens have discovered new physics which we don’t know about”.
etc.. etc..
Any unexplained phenomena, terrestrial or otherwise, can be explained by ‘aliens’, and for any skeptical counter-argument, the specifics of ‘aliens’ can be varied to fit the facts.
Therefore, as things stand with our current knowledge, ‘aliens’ is simply not a good explanation, regardless of the prior and posterior probabilities.
The biggest problem with the argument is that, given our current knowledge about the specific details of extraterrestrial civilizations, the term ‘aliens’ in P[aliens] does not fulfill the hard-to-vary criterion of a good explanation.
Skeptic: “If it’s aliens, why haven’t they been trying to contact us”
Post-hoc variation: “Because of the Prime Directive”
Skeptic: “If it’s a physical vehicle, why does it not obey the laws of physics”
Post-hoc variation: “Because the aliens have discovered new physics which we don’t know about”.
etc.. etc..
Any unexplained phenomena, terrestrial or otherwise, can be explained by ‘aliens’, and for any skeptical counter-argument, the specifics of ‘aliens’ can be varied to fit the facts.
Therefore, as things stand with our current knowledge, ‘aliens’ is simply not a good explanation, regardless of the prior and posterior probabilities.