…the expectation that life — from bacteria to sentient beings — has or will develop on other planets as on Earth might be based more on optimism than scientific evidence.
Bayesian probability is named after 18th century English mathematician and theologian Thomas Bayes. Yes, you can blame him for bursting your bubble.
But here’s the gist of it. In having ONE earth with ONE example of life and evolution on this planet, we have a sample size of exactly ONE. Statistically, that’s horse feathers; you can’t assume anything about the rest of the universe with a sample size that tiny.
Even by throwing around “magical” words like “billions” or “trillions”, meaning galaxies, stars, exoplanets – it still doesn’t guarantee any success in finding extraterrestrial life.
To borrow from Karl Popper, as long as the existence of extraterrestrial life or intelligence is not falsifiable (meaning you would have to check every exoplanet around every star), you could continue the search for ET forever. I’m not sure that this is in line with the scientific method; ideally you’d be looking objectively at what’s out there and trying to understand what you see from that standpoint.
We may just be all alone on our pretty blue marble.