[I]f each instrument could do its own work, at the word of command or by intelligent anticipation, like the statues of Daedalus or the tripods made by Hephaestus, of which the poet relates that ‘Of their own motion they entered the conclave of Gods on Olympus.’ A shuttle would then weave of itself, and a plectrum would do its own harp playing. In this situation managers would not need subordinates and masters would not need slaves.