"How could any number of people--all together--know enough? It reminded Seldon of a puzzle that had been presented to him when he was young: Can you have a relatively small piece of platinum, with handholds affixed, that could not be lifted by the bare, unaided strength of any number of people, no matter how many? The answer was yes. A cubic meter of platinum weighs 22,420 kilograms under standard gravitational pull. If it is assumed that each person could heave 120 kilograms up from the ground, then 188 people would suffice to lift the platinum. --But you could not squeeze 188 people around the cubic meter so that each one could get a grip on it. You could perhaps not squeeze more than 9 people around it. And levers or other such devices were not allowed. It had to be "bare, unaided strength." In the same way, it could be that there was no way of getting enough people to handle the total amount of knowledge required for psychohistory, even if the facts were stored in computers rather than in individual human brains. Only so many people could gather round the knowledge, so to speak, and communicate it."