THB: Extraterrestrial life exists

It seems some of the links I used as sources in R2 don't work. For those links, please copy the expression I was sourcing a value for (e.g. " 1-(0.5^(1/(10^29))) ~10^-30" for source 3) into Wolfram Alpha (which is sent by the link). In the interests of making refutation easier, I have condensed Con's argument into manageable points: 1) My (Pro's) R2 arguments didn't address the motion- it doesn't try to justify a 100% certainty in the belief that alien life exists. 2) Ancient cave paintings of what are supposedly aliens may not actually be depicting aliens. 3) Eyewitness testimony is unreliable. 4) Video evidence can be faked. 5) There is no definitive evidence from space of extraterrestrial life. In response to point 1), my argument does address the motion because, as I specified, I have argued (in my view, quite convincingly) that it is overwhelmingly more likely that extraterrestrial life exists than that it does not. Doing so does indeed justify the claim that "This house *believes* extraterrestrial life exists", as the motion doesn't claim certainty. If one considers a claim to be more likely to be true than to not be true, one *believes* in that claim, as per the wording of the motion. Had the motion been "This house knows to 100% certainty that extraterrestrial life exists", I would have failed to address it. However, this is not the motion being discussed. Points 2:4 are essentially refutation to arguments which I never put forward in the first place; The majority of extraterrestrial life is most likely microbes or similar mono-cellular organism- the motion never proposed *sentient, humanoid* life, although I believe a similar probabilistic argument could be made in favour of such a notion. It may very well be the case that cave paintings were never meant to depict aliens, that all eyewitnesses of extraterrestrial life on Earth are lying or delusional, and that all video evidence of UFOs is faked, but none of this would make my probabilistic argument in R2 any less valid; it is overwhelmingly likely that extraterrestrial life exists that has never made contact with humans. In response to 5, I'd like to point out that there is considerable evidence that may point to extraterrestrial life: the ALH-84001 meteorite (see source 1) is one such example. However, even if there were absolutely no evidence for extraterrestrial life [NB: there is], that wouldn't necessarily mean such life does not exist; imagine a form of extraterrestrial life on a body orbiting a random star in a random galaxy in our universe; the odds of it being within range of our detection are unimaginably small, and the odds of it being in our solar system- as would be necessary for us to expect considerable evidence for such life- are even smaller. Absence of evidence is not necessarily evidence of absence, especially in cases where one wouldn't necessarily expect evidence to be present if the claim were true. I'd also doubt Con's claim that: "To justify any claim you need evidence" There are some things we can know "a priori" (see source 2), meaning that we don't need to establish them with empirical evidence and observation. One such example is the claim that "All bachelors are unmarried"; by definition of those words, it must be true- no evidence needed. Likewise, probabilistic statements like the one I'm making (i.e. that it is more likely that extraterrestrial life exists than that it does not) do not need to be backed by empiricism, and approximations and mathematical deductions such as the ones I used are valid to establish a probabilistic claim. Myself and Con agree that extraterrestrial life may exist. I feel I have argued convincingly in R2 that it is overwhelmingly more likely that it does exist than that it does not, and I feel Con has failed to refute this. Hence, we should believe that it does exist. Hence THB extraterrestrial life exists. Thank you for your time. Sources: [1]: "NASA scientists and their colleagues announced they had spotted possible signs of Mars life in a meteorite." http://www.space.com... [2]: "relating to or denoting reasoning or knowledge which proceeds from theoretical deduction rather than from observation or experience." https://www.google.co.uk...