“This one isn’t,” Auberson said. “This one’s human.”

“Oh?” Elzer raised an eyebrow. “Aren’t you exaggerating just a bit?”

Auberson sagged back into his chair. He looked around the mahogany-lined room at the other members of the Board. “Would somebody please tell this… this high-priced bookkeeper just what the HARLIE project is all about?”

The other Directors stared back, impassive. Auberson had committed a serious breach of courtesy — he had insulted one of them. White-haired Griff, the oldest member of the Board, coughed and looked at the ceiling. Hudson-Smith, down the table, made a show of refilling his pipe. Next to him, young Clintwood took off his glasses and examined them for dust If Aubie was going down the tubes, he was going to go alone. The only one in the room not appreciably cool to Auberson was Miss Stimson, the executive secretary.

After a bit, after he had let the silence make its point, Dome, the Chairman of the Board, took his thick cigar out of his mouth and grunted, “I’m sure you can do it, Auberson. You know more about this piece of hardware than any of the rest of us.” He replaced his cigar and settled himself in his chair.

Auberson didn’t like the emphasis on “piece of hardware.” Didn’t they understand? HARLIE was more than that, much more. “All right,” he said. “I will. The HARLIE project is the logical extension of Digby’s work with the variable brain path—”

“The variable brain path?” asked one.

“The Mark IV judgment unit. Instead of base two, it uses base twelve. With compaction we can increase its precision by a power of twelve for each stage. First stage compaction is twelve squared, second stage is twelve cubed. Third stage compaction gives us twelve to the fourth power, or 20,736 possible choices.”

“You’ve lost me,” said Elzer. “Now tell it in English.”

Auberson suppressed an impulse. He forced himself to be calm. “I assume you mean one-syllable words?” He didn’t wait for an answer. “Binary code means your machine can make only two possible decisions — on or off, ‘yes’ or ‘no.’ There’s no possibility for ‘mostly yes,’ ‘somewhat yes,’ ‘slightly yes,’ ‘maybe yes,’ ‘maybe yes and maybe no,’ ‘maybe no,’ ‘slightly no,’ ‘somewhat no,’ ‘mostly no’ — there’s no selectivity. It’s either/or. By increasing the number of choices you increase the range of the machine’s judgment. Base three gives you ‘yes,’ ‘no,’ and ‘maybe.’ Base five adds ‘slightly yes’ and ‘slightly no.’ Give it base ten to work with and it’s a pretty selective system. Base ten,” he explained, “is the system most people use.” He held up his hands, spread his fingers and wiggled them. “See? Ten fingers. That’s if you count on them.” Elzer ignored it.

He continued. “We use base twelve in the judgment units for mathematical reasons. It eliminates some of the problems inherent in using tens. The nearest way I can explain it is that twelve divides into neater pieces. Ask a mathematician sometime about the advantages of base twelve over base ten.”

“Got that,” said Clintwood. “How do you do it with computers?”

“You mean the circuitry? I’m not sure I can answer that. I don’t know enough about it.”

“Can you give me an idea?” the younger man asked.

“Well, are you familiar with fluidics?”

“Sort of.”

For the rest of the Board, Auberson explained: “Fluidics is a term used to describe computers or computer circuits based on the flow of a liquid or gas, rather than on the flow of electricity. Just as a transistor uses a small current to modify a large one, a fluidic circuit can use a small flow of liquid to modify a bigger one. There’s an important difference, though. An electric circuit is either/or; either the circuit is on or it’s off. With fluidics, however, you can vary the force of the modifying flow and vary the modification of the bigger. You can push the ‘current’ to be modified all the way over to the ‘yes’ side or to any notch in between. Because your major flow responds in proportion to the force of the modifying flow, you can have your full range of ‘yes’ to ‘no’ responses.”

“How does it do that?”

“It’s the simplest thing. The major flow, the one to be modified, is forced down a channel, which splits into several different directions. The modifying flow is directed into or against the major flow and deflects it into the desired channel. The pressure of the modifying flow is the variable thing. The harder it pushes at the major flow, the farther over it’s deflected. If the major flow is fast enough, you can vary its response several hundred times a second. What you have is a system that responds with surprising accuracy to the pressure of a fluid in a pipe. They’ve been using fluidics arrangements in industry for several years now, and also in the fuel feed systems of jets.

“The judgment circuit is the electronic equivalent of a fluidic unit. It measures the voltage, or pressure, of an electrical current and responds in degree to it. It’s very much like the way the human nervous system works. If a nerve cell releases a strong enough charge, it’s enough to set off the nerve cell next to it. Our judgment units do the same kind of thing; that’s how we can duplicate the action of a fluidic unit — or more importantly, of the human brain. With hyper-state layering, we can compress the circuitry into a size comparable to that of an equivalent piece of brain tissue.”

There were one or two nods around the table. Clintwood looked up from his notepad. “You used another term. Compaction?”

“Right,” said Auberson. “Compaction is the term we use for giving the unit a second level of judgment circuits. It increases the number of choices by one power of the base number — twelve times twelve gives one hundred and forty-four choices in any given situation. One hundred and forty-four degrees between ‘yes’ and ‘no.’ Want more precision, increase the number of levels. Each level increases the number of choices by twelve times.”

“Doesn’t that run into an awful lot of circuitry?”

“No. We can use the same circuits for almost any level of judgment. All the machine has to do is keep straight which is which. The machine makes a choice, decides it isn’t precise enough, shifts down one level and runs the thing through the same circuitry again. That’s compaction. It allows us to get a high degree of precision with a lot less circuitry. If Handley were here, he could explain it. Don Handley is the design engineer on the HARLIE project.”

“You can’t explain it?” asked Elzer acidly.

“I can explain what I know,” Auberson said, suddenly cautious.

“I thought you knew what HARLIE was. You are the chief of the project aren’t you?”

“I’m a research psychologist not an engineer. Anything I’ve picked up about computers, I’ve had to learn specifically on this project I—” He stopped himself. Justifications wouldn’t do any good here. He’d have to try something else. “Elzer, do you drive a car?”

The little man was startled. “Yes, of course.”

“What kind?”

“A Continental.”

“This year’s, I suppose?”

“That’s right.” He said it proudly.

“You knew that its Thorsen Auto-Pilot was one of our units, didn’t you?” He didn’t wait for an answer — it was a rhetorical question. “It was made possible by the variable-path circuits that we’ve been producing for the past four years and marketing as the Mark IV. Basically, that’s a simplified version of one type of HARLIE function module.”

“You mean HARLIE’s a giant judgment circuit?”

“HARLIE is a human brain — with solid-state circuitry instead of organic nerves. We use the judgment circuits to duplicate the human functions. The important part of the human brain is actually a series of very complex judgment paths. They don’t work exactly the same as HARLIE’s, but close enough. The difference is in mechanisms, not basic principles. If a nerve impulse is strong enough, it can trigger other nerves around it; the number of nerves reporting allows the brain to interpret the strength of the original stimulus. HARLIE’s circuits work the same way. The strength of the ‘yes’ impulses (or ‘on’ circuits) determines the interpretation. Just for HARLIE to complete one thought involves several thousand compacted judgment boxes.”