Again, not in the truest mathematical sense of the word, no, but I can reasonably rule it out in most practical senses: a) You look like a human b) You write h

Again, not in the truest mathematical sense of the word, no, but I can reasonably rule it out in most practical senses: a) You look like a human b) You write human language c) We have not seen any direct evidence for any kind of humanoid alien life, but we have seen lots of evidence for humans existing. d) If you were an alien spying on human culture, you wouldn't waste your time on Hacker News :). Does this fully "rule out" the possibility of you being an alien? No, I suppose you could be an alien in a human skin suit who learned English, and maybe aliens are really interested in software engineering forums, but I can practically rule it out just playing the odds.