The Extensions of Man

As we have seen in the last chapter man’s capacity for storing and retrieving information within his own brain is limited. Although prehistoric man must of necessity have invented a variety of ways of aiding his memory, the only aids to survive have been paintings and drawings. Knots have been used for the same purpose in many periods of history. Even today you may still tie a knot in your handkerchief, at the same time making an association with it and with something you want to remember. Herodotus reports the use of knots by the Persian King Darius. This king is said to have given instructions to the Greeks guarding a bridge to untie one knot each day and to remain guarding the bridge until all the knots had been untied. The people of Peru used an elaborate form of knots known as “quipus” which consisted of knotted cords of different colours with other cords hanging from them.