And no-one could say they were fools
But the axes they made
They failed to upgrade
‘cause no-one could teach them the rules.
In considering the evolution of human intelligence there is uncertainty about when an effective language first emerged and there is also a mystery of the early stone hand axes, which were made to the same design for about a million years. If the early hominins who made these tools were really that intelligent one might expect that someone in more than 70,000 generations would have found a way of making better stone hand axes.