In the previous installment of this series, I showed that – contrary to assumptions made by pioneers of artificial intelligence such as John von Neumann – the human brain bears virtually no resemblance to a digital computer.

Von Neumann in particular should have realized this. He had a broad knowledge of physical science and was in contact with leading researchers in the areas of biophysics and neurophysiology.

But he and others banked on the discrete, “all-or-nothing” nature of neural impulses, which superficially appear analogous to the “0” and “1” of digital computers. He assumed this would allow researchers to ignore the complicated biology and biophysics of real, live neurons and treat the brain as a digital system.

If the goal is to understand how the brain actually works, that was a stupid mistake. But it did inspire early successes in developing computers and primitive AI systems, including the artificial neural network approach that eventually led to today’s “deep learning” systems.