I don t reject the possibility of a god; I simply don t have sufficiently compelling compelling evidence to think a god exists.
I also accept the possibility of life on other planets. Given what we know about organic chemistry, evolution, the ubiquity of carbon and water etc. I think this is likely. Of course, I don t know there is extraterrestrial life since, as you pointed out, it is unverified. Yes, this is an appeal to probability. Unlike say, "appealing to authority" appealing to probability is not a logical fallacy.
I don t think extraterrestrial life or gods are philosophical concepts. Both of these things either exist or they don t.
I don t know what kind of "biased worldview" you think I have. You ll have to be more specific if you want a better answer. If you mean I have a naturalistic bias you are certainly right, however, I don t think that is irrational. Science has succeeded dramatically in finding naturalistic explanations for previously inexplicable phenomena.