There is a strong and, it seems, almost irresistible tendency in the human mind to interpret human functions in terms of the artifacts that take their place, and artifacts in terms of the replaced human functions. The power engine, with its levers and joints and its voracious fuel consumption, was a slaving giant, and, correspondingly, the human or animal body was a fuel-burning power machine. The modern servomechanism is described as perceptive, responsive, adaptive, purposive, retentive, learning, decision-making, intelligent, and sometimes even emotional (but this last only if something goes wrong), and, correspondingly, men and human societies are being conceived of and explained as feedback mechanisms, communication systems, and computing machines. The use of an intentionally ambiguous and metaphorical terminology facilitates this transfer back and forth between the artifact and its maker.