Metaphor is a helpful technique for explaining things. A good way to help someone understand a new concept is to liken it to something that the person already understands.
Explaining what voltage is? Use the tried and true method of analogizing it to water pressure. Electrons are “pushed” through a wire in a way reminiscent of how water is pushed through a pipe.
It’s important to not become overreliant on metaphor. A metaphor is an abstraction that hooks onto something familiar in order to provide a foothold for understanding. But abstractions necessarily hide information.
I think about this whenever someone on a podcast says something like “consciousness is just computation performed by the brain”.
A computer is a compelling metaphor for how brains seem to process information. Neurons exchange electrical and chemical signals in response to stimuli, and our latest computing systems emulate these processes to great effect. But to explain the brain as “a computer” feels circular. It’s a map being used as shorthand for a territory.
And computation is only the most recent in a long series of maps used to explain the territory of the brain. Before computers, people saw the brain as an intricate telegraph network relaying signals. Before that, it was a clockwork mechanism. René Descartes was big on this in the 17th century, likening some aspects of brain function to clocks and machines, others to hydraulics and fluid flows.
I find this history of using $CURRENT_THING as a metaphor for how the brain works humbling. On the one hand, it shows how scientific understanding and technology have progressed in concert over the centuries. But it also makes claims of the brain being a computer seem kind of arrogant. Who’s to say that this isn’t as partial an understanding as Descartes’?