in an electronic age when we’re familiar with the process of sending signals through
electrical circuits. In an earlier age, dominated more by mechanical technology,
Sigmund Freud subtly employed a “steam engine” metaphor to account for aspects
of the brain’s activity when he wrote of the effects of repression “building up pressure”
to the point of “sudden release.” In an even earlier age, Aristotle’s metaphor was of the
brain as a cold sponge that functioned to keep the blood cool.
In a sense, we are forced to use metaphors mainly because we cannot obtain direct
physical evidence of linguistic processes in the brain. Because we have no direct
access, we generally have to rely on what we can discover through indirect methods.
Most of these methods involve attempts to work out how the system is working from
clues picked up when the system has problems or malfunctions.