The counter-counter argument is that while we’ve been here for a comparative blink of an eye, we’ve left behind 4 orders of magnitude more stuff than just nests, bones, and a feather or two.

If humanity vanished today, in 1 million years almost all of our artifacts would be gone or burned under miles of subduction.

In 10 million years there would literally be nothing left.

The fossils we do have are of highly successful species in that geography. It’s a matter of chance, leaving behind a fossil, after all.

And unlike biological matter that can fossilize, industrial structures etc do not. All our manufactured stuff has very short life once it reaches the crust and starts getting compacted.

The more time you add, the better the odds we’d find this evidence lost.

And if this wasn’t a global, but more localized pre-human civilization, the evidence would be thinner still.

Which is why this isn’t a scientific hypothesis really. It’s more showing you the limits of scientific inquiry into the deep history of Earth.

This is what I always say to "Why haven't we found any aliens yet??"

Hell, we wouldn't even have known about the existence dinosaurs, lifeforms on THIS VERY PLANET, if we hadn't chanced upon their remains.

As such it seems impossible for life to have reached interstellar travel anywhere in the Milky Way before at most a few million years ago, otherwise we would see it.

Which is weird because life surely can’t be that rare in the entirety of space time.

Of course the galaxy could be teaming with non interstellar life, but once you reach mankind’s level of sentience and technology it dormant seem a massive jump to interstellar, and once that happens there’s no way to put the genie back in the bottle.

Places where there is suddenly a vast collection of foreign rocks from the other side of the world that can't be explained by glaciers.

Radioactivity from nuclear tests that can't be explained by stellar phenomena and leave a layer of weird isotopes and isotope ratios all around the world, as we already have done.

And while we aren't to the point we'd have found this quite yet necessarily, evidence on the Moon where unlike Earth evidence probably would in fact persist for millions of years, especially if it ever attained any scale, e.g., "a large complex of cities" might still leave a visible mark on the surface easily visible to modern satellites and clearly with no other explanation available as to what caused it.

People get stuck on the idea that the only way to determine there was intelligent life earlier is to find a super complicated artifact which obviously can't survive, but there are footprints we've left in the world that are way, way larger than a cell phone or even a major city.

I don't find it hard to believe we've lost entire human civilizations. In fact I'd call it the smart bet. Maybe those civilizations were even a bit more sophisticated than we'd have thought, with maybe an earlier and entirely unknown Iron Age popping up somewhere for some period of time or something. But this is the first major technological civilization this planet has ever seen, even across geological time scales. And those lost human civilizations never reached to the level where they took all the easy resources like we have, because if they had, we wouldn't be able to get them. Some resources we call "non-renewable" do replenish on a few million year time scale, but we also pull lots of resources out of billion-year-old rocks, such as copper mines in northern Michigan which are pulling resources out of pre-Cambrian rocks. Clearly nobody else has been there, at scale.

We have plenty of fossil evidence from, from your example, a million year old hominids. Far more than we would need to expect to see evidence of civilization.

Subduction makes up for a tiny tiny proportion of where coastal land "goes" in any age.

You'd need an enormous set of coincidences for a past civilization of hominids to go unnoticed.

How so? We know how it forms, there is no real gap in understanding there. What could lead to the kind of distribution of oil and gas fields we can observe?