The answers to Richard Thaler’s Edge 333 question are all worth reading, but Nicholas G. Carr’s thoughts about metaphors for the brain is especially good:

I think it’s particularly fascinating to look at how scientific beliefs about the functioning of the human brain have progressed through a long series of misconceptions.

Aristotle couldn’t believe that the brain, an inert grey mass, could have anything to do with thought; he assumed that the heart, hot and pulsing, must be the source of cognition, and that the brain’s function was simply to cool the blood.

Descartes assumed that the brain, with its aperture-like “cavities and pores,” was, along with the heart, part of an elaborate hydraulic system that controlled the flow of “animal spirits” through the “pipes” of the nerves. More recently, there was a longstanding belief that the cellular structure of the brain was essentially fixed by the time a person hit the age of 20 or so; we now know, through a few decades’ worth of neuroplasticity research, that even the adult brain is quite malleable, adapting continually to shifts in circumstances and behavior.

Even more recently there’s been a popular conception of the brain as a set of computing modules running, essentially, genetically determined software programs, an idea that is now also being chipped away by new research. Many of these misconceptions can be traced back to the metaphors human beings have used to understand themselves and the world (as Robert Martensen has described in his book The Brain Takes Shape).

Descartes’ mechanistic “clockwork” metaphor for explaining existence underpinned his hydraulic brain system and also influenced our more recent conception of the brain as a system of fixed and unchanging parts.

Contemporary models of the brain’s functioning draw on the popular metaphorical connection between the brain and the digital computer. My sense is that many scientific misconceptions have their roots in the dominant metaphors of the time. Metaphors are powerful explanatory tools, but they also tend to mislead by oversimplifying.

What other contemporary metaphors are misleading us about our world today?