The Information - James Gleick [116]
It was true, Gerard said, that his field was being profoundly affected by new ways of thought from communications engineering—helping them think of a nerve impulse not just as a “physical-chemical event” but as a sign or a signal. So it was helpful to take lessons from “calculating machines and communications systems,” but it was dangerous, too.
To say, as the public press says, that therefore these machines are brains, and that our brains are nothing but calculating machines, is presumptuous. One might as well say that the telescope is an eye or that a bulldozer is a muscle.♦
Wiener felt he had to respond. “I have not been able to prevent these reports,” he said, “but I have tried to make the publications exercise restraint. I still do not believe that the use of the word ‘thinking’ in them is entirely to be reprehended.”♦♦♦
Gerard’s main purpose was to talk about whether the brain, with its mysterious architecture of neurons, branching dendrite trees, and complex interconnections alive within a chemical soup, could properly be described as analog or digital.♦ Gregory Bateson instantly interrupted: he still found this distinction confusing. It was a basic question. Gerard owed his own understanding to “the expert tutelage that I have received here, primarily from John von Neumann”—who was sitting right there—but Gerard took a stab at it anyway. Analog is a slide rule, where number is represented as distance; digital is an abacus, where you either count a bead or you do not; there’s nothing in between. A rheostat—light dimmer—is analog; a wall switch that snaps on or off, digital. Brain waves and neural chemistry, said Gerard, are analog.
Discussion ensued. Von Neumann had plenty to say. He had lately been developing a “game theory,” which he viewed effectively as a mathematics of incomplete information. And he was taking the lead in designing an architecture for the new electronic computers. He wanted the more analog-minded of the group to think more abstractly—to recognize that digital processes take place in a messy, continuous world but are digital nonetheless. When a neuron snaps between two possible states—“the state of the nerve cell with no message in it and the state of the cell with a message in it”♦—the chemistry of this transition may have intermediate shadings, but for theoretical purposes the shadings may be ignored. In the brain, he suggested, just as in a computer made of vacuum tubes, “these discrete actions are in reality simulated on the background of continuous processes.” McCulloch had just put this neatly in a new paper called “Of Digital Computers Called Brains”: “In this world it seems best to handle even apparent continuities as some numbers of some little steps.”♦ Remaining quiet in the audience was the new man in the group, Claude Shannon.
The next speaker was J. C. R. Licklider, an expert on speech and sound from the new Psycho-Acoustic Laboratory at Harvard, known to everyone as Lick. He was another young scientist with his feet in two different worlds—part psychologist and part electrical engineer. Later that year he moved to MIT, where he established a new psychology department within the department of electrical engineering. He was working on an idea for quantizing speech—taking speech waves and reducing them to the smallest quantities that could be reproduced by a “flip-flop circuit,” a homemade gadget made from twenty-five dollars of vacuum tubes, resistors, and capacitors.♦ It was surprising—even to people used to the crackling and hissing of telephones—how far speech could be reduced