To Sayonara

 

I concede your point. I believe that near intelligence has occurred only in the last 50 million years, which is not the same as proving it to be a fact.

 

It is possible, though I would consider it unlikely, that some more ancient cephalopods, and possibly some dinosaurs had near intelligence earlier than that. However, I have seen little good evidence to prove my belief wrong. Perhaps you have such evidence?

I think the problem we have there is that any evidence for it would be unlikely to survive the test of time.

 

I don't think there is anything wrong with setting a limit such as your 50 million years based on what we do know, as long as we acknowledge the uncertainty in the figure with a caveat.