<quoted text>That's untrue; we don't know if life will develop on any planet other than Earth. We have no knowledge if life will develop in any galaxy other than the Milky Way.
We would have to know of life in another galaxy to claim, "the odds that life will develop on a planet in a galaxy is 100%."
<quoted text>That's just compounding error after error.
Belief in extraterrestrial life is based entirely on faith without any scientific evidence.
Look it is not a belief or desire , it is a question and prediction by odds. If you do not understand that, you may as well give up.
We have an example , it is 100% odds that life formed on a planet in a galaxy.
We have no reason to think other galaxies would be any different.
You think because we don't have an example other than our own
there can be no prediction, but the only example IS the prediction.
We also know the elements that make life are abundant in the universe. We know water is abundant in the universe. We also know that life formed on Earth in a hostile molten environment, and survived a frozen Earth. Was destroyed 5 times and returned to repopulate the Earth.
The odds are really even higher than you think that life could have formed more than once in this galaxy. Given the criteria
habitable zone and elements as well as its ability to recover from extinction. But this is not faith or belief is is a guess based on the evidence and criteria.