An idea with more acceptance on this board is that we are more likely in a simulation than in the real world. This is more accepted at least in the sense that posts that support this hypothesis are not vote-bombed down.
An interesting thing to ponder is that in a simulated world we would be very likely to have what would be essentially aliens among us. The intelligences running the simulation would have not particular reason not to intervene in the simulation when and how they felt like it in ways that violated the physics of the simulation. These interventions would be, by the usual definitions of the terms, miraculous in that they were events perpetrated by a powerful intelligence outside of the "natural" laws of physics and causality.
Aliens, gods, the entity in the next universe up running the simulation, these are all just different hypotheses to explain the same types of events: apparent interventions that to a naive our our current understanding of physics appear impossible. Tech beyond our own is indistinguishable from magic, it is really only our priors that have some of us attributing those to gods, others attributing those to aliens, others of us attributing it to the simulators, and finally some of us claiming that these things are so unlikely that they deny their is enough evidence to believe any of them happened at all.
Recently I've been struck with a belief in Aliens being present on this Earth. It happened after I watched this documenary (and subsequently several others). My feeling of belief is not particular interesting in itself - I could be lunatic or otherwise psychological dysfunctional. What I'm interested in knowing is to what extend other people, who consider themselves rationalists, feel belief in the existence of aliens on this earth, after watching this documentary. Is anyone willing to try and watch it and then report back?
Another question arising in this matter is how to treat evidence of extraordinary things. Should one require 'extraordinary evidence for extraordinary claims'? I somehow feel that this notion is misguided - it discriminates evidence prior to observation. That is not the right time to start discriminating. At most we should ascribe a prior probability of zero and then do some Bayesian updating to get a posterior. Hmm, if no one has seen a black swan and some bayesian thinking person then sees a black swan a) in the distance or b) up front, what will his a posterior probability of the existence of black swans then be?