[Houshalter]

Well that's an interesting point. There is survivorship bias. If the key event for life to thrive never happened, then we wouldn't be here to talk about it, but maybe some other world would have evolved intelligent life instead and they would be.

If you assume that a hybrid is necessary for intelligent life (which is a crazy, unlikely, implausible assumption, I know) then it doesn't matter if it only happens in one out of a billion worlds, on the one world it does happen in, there will be intelligent people around to talk about how unlikely it is.

Now maybe it's not so implausible. Pigs are some of the smartest animals, and something weird happened a few million years ago to jump start human evolution such a crazy amount. Still seems pretty unlikely IMO though, but I'll raise my probability estimate of it slightly.