>>12523176The biological history of the Earth is pretty compatible with what we see in terms of extra-terrestrial life. Simple prokaryotic cells only took about 500 million years to sprout up in Earth but it took some like 2 billion years for anything more advanced than essentially bacteria to commence.
The likely reality is that life simple life probably exists in abundance, multicellular life is probably rare, and advanced intelligent multicellular life is ultra rare.
If anything I'd wager that it's more common for life to begin than it it is for it to evolve into something as complex as human.
