I don't base my theories on them. But I am just saying that really smart people, like Stephen Hawking, have done the math and are nearly certain of extraterrestrial life.
They prove the likelihood of aliens existing, and the bigger the chance, the more certain you can be.
Probability plays a key role in several modern applications. There's a probability of et existing mainly due to the fact we exist. There's this documentry I saw recently that tried to relate myths/god with et and that ppl could've been mistaken etc. I'm sure you can find it online ..
What probability has to do with it: I take a little bag and fill it with red and white marbles. If I pick out a white one, there are most defiantly aliens out there.
I once met an alien...I found it in my shed....we had such a good time.....we even flew past the moon on a bike....his name was ET...when it phoned home he gave me 10 DOLLAR and went home