People today live longer than at any previous time in history. They can run faster, jump higher, and perform all sorts of feats that would have been thought incredible during earlier epochs.
Yet nobody has ever lived much beyond the age of 120 (122 is in fact the recorded limit), and nobody can jump 20 feet up in the air. In other words, there are limits.
I suspect there are similar limits on the potential of human intelligence. After all, the brain is a biological organ. As astonishing as it is, it is not infinite.
But what are those limits, at their theoretical extreme? And how would we ever know if we have reached those limits? What, exactly, is the intellectual equivalent of living to the ripe old age of 122?