But at the same time the study has disappointed me, because even if the theory was correct, it did not much enlighten one about the motor sys- tem-it did not, for example, tell one how to go about programming a mechanical arm. It suggested that if one wishes to program a mechanical arm so that it operates in a versatile way, then at some point a very large and rather simple type of memory will prove indispensable. But it did not say why, nor what that memory should contain.