Because we do not understand the brain very well we are constantly tempted to use the latest technology as a model for trying to understand it. In my childhood we were always assured that the brain was a telephone switchboard. (‘What else could it be?’) I was amused to see that Sherrington, the great British neuroscientist, thought that the brain worked like a telegraph system. Freud often compared the brain to hydraulic and electro-magnetic systems. Leibniz compared it to a mill, and I am told some of the ancient Greeks thought the brain functions like a catapult. At present, obviously, the metaphor is the digital computer.

–John R. Searle,
MINDS, BRAINS AND SCIENCE, p 44

 

Published in 1984. I would update Searle with, “At present, obviously, the metaphor is the Internet, the brain as a complex network of adaptive connections.”

Problem is, the brain is not very similar to anything. Comprehension is further hampered by the fact that “the brain” has no clear boundaries. Its behavior requires a body and an external environment. Not to mention the recursive challenge of the brain being the primary tool used to comprehend itself.