[glenstein]

To your point, one of the most remarkable things I've read about both Mars and Venus, is that there was a time billions of years ago when they had more moderate temperatures and liquid water.

In a way, it's a tragedy that human civilization has only emerged at a time when both Mars and Venus have become much more uninhabitable than they used to be.

[ASalazarMX]

Probably because the period where the three (or even Earth and another) of them were inhabitable enough to sustain a technological civilization was very small, if it happened at all.

[pfannkuchen]

Or we cycle through them and forget every time.

[lavelganzu]

It's a fun idea to explore in fiction, but it certainly didn't happen. The evolution of our species is too recent.

[pfannkuchen]

I’m only 1% serious, but how do we know for sure which direction evolution went in within the ape family?

It seems not entirely unplausible that we have at some point in the scientific chain of custody assumed the “lesser” apes “evolved into” the “more advanced” human.

But a species could easily branch and have the branch lose its geographic portability features (e.g.ability to manipulate environment, most exogenous behavior learning-based) if they are no longer selected for in a particular environment, and I’m not aware of anything in the fossil record that firmly establishes directionality. Am I wrong?