There is absolutely zero evidence for this either way. We assume this is the case, but there's actually no way to ever know for sure. It's completely possible that life emerged and went extinct on this planet many times. Problem is it was so long ago that any fossil evidence has been either buried so far that we can never reach it, or subducted into the mantle and melted down. Absolutely no way to tell.

▲

vlovich123 2 days ago | parent [-]

It was so long ago that it would be buried deep under the ocean and we haven’t even explored well the ocean floor. And fossils wouldn’t really tell you whether there was one origin or another.

And you’re right, assuming those fossils even managed to survive in the first place and not get destroyed. And that’s ignoring that early life would have been microscopic and we wouldn’t really see fossils of that.

▲

d1sxeyes a day ago | parent [-]

Why did it stop?

	▲	vlovich123 a day ago \| parent [-]
		Do we have evidence that it stopped? Or just that we don’t know where to look and what to look for? But even if it did, one clear argument could be that the conditions on Earth when it happened would have been very very different than the earth today. Lots more volcanic activity, lightning storms, and UV radiation. We don’t know the exact conditions needed to create life from inorganic precursors so we don’t have a solid hypothesis of was there multiple origins or a single or is it still happening today. But given we have the beginnings of evidence of life on Mars, Titan, and Triton, and that it would make sense since we know life must arise naturally out of non-life origins (since there was no life at the Big Bang), I would venture to guess that life is both rare and common. Intelligent life also seems common although less common than life overall (other primates, dolphins, Elephants, ravens/crows, and cephalopods are all quite intelligent). Intelligence + tool use is also not uncommon but rarer (we’ve caught animals on tape using tools). Advanced industrial civilization is the only thing so far that we only have a single existence evidence for - is that unique, can there ever only be one on a planet at a time, or can there only be one ever when conditions are right? Eg we wouldn’t have gotten very far if we were on the planet earlier and didn’t have dinosaur bones to power our industry with - the jump from whale oil to nuclear/photovoltaics/wind turbines seems unlikely but maybe it would happen anyway, just longer.