The Zen master tells us that an omnipresent idea can be hidden by its own omnipresence - the forest lost among the trees. In our normal daily behavior we are most estranged, most in the grip of an illusory idea of the self. Every enchanting inclination of pride and its ego, of convention and its master - social training - conspires to maintain the illusion. The semanticist calls it the inertia of old premises. And this is what holds our analyses of consciousness within fixed limits.

SHE WROTE "Prudence Lon Weygand" at the foot of the log tape, started it rolling through the autorecorder, made the synchronous shift to Flattery's tape as he took over the board. The counter said it was her thirty-fifth change of shift.

Flattery squirmed in his couch, settling himself for the four-hour watch. Reflections on the dial faces were hypnotic. He shook his head to bring himself to full alertness, heard the hiss of fabric as Prudence got out of her couch. She stood there a moment stretching, did a dozen deep-knee bends.

How easily they accept the possibility that I'm the executioner, Flattery thought. He noted how wide awake and alert Prudence appeared. This four-hours-on, four-hours-off routine could be endured as long as no serious problems arose, but it played hob with the metabolic cycle. Prudence should be headed for food and rest, but she obviously was wide awake.

She glanced at Flattery, saw he was settled in for the watch, checked the repair log. Nothing was flagged urgent. That made it a bit more than twenty-five hours with nothing more than minor adjustments on the big board. Smooth. Too smooth.

Danger keeps you honed to a fine edge, she thought. Extended peace makes you dull.

But she wondered if Project had anticipated the special danger she had found for herself, and she thought: Am I the stick to beat not only the others, but myself?

The line of her own research seemed so obvious, though: define the chemical sea in which consciousness swam. The ultimate clue lay, she thought, in the serotonin adrenalin fractions. The thing she sought was an active principle, something between synhexyl and noradrenalin, a flash producer of neurohormones. The end product would be the root-stimulator of human consciousness. Find that chemical analogue and she could give fine detail to the workings of consciousness; provide a point-to-point sequencing which they could follow with machine simulation.

On the course she had chosen, the dangers to her person were enormous. She had no other guinea pig upon whom to test the derivatives her ingenuity produced. The possibility of deadly error was always present. The last substance, a relative of cohoba with an extra nitrogen addition, had ignited her mind, transported her into a weird consciousness. All sounds had become liquids which merged within her to be translated by a centrifuge process of awareness. It had been a terrifying experience, but she refused to stop.

It was only possible to make the tests during the deep rest periods in her own private cubby, and there was always the possibility some physical response would betray her. She could not afford that; the others would unite to prevent the tests, she knew: Such was their conditioning.

"You'd better get something to eat and try to rest," Flattery said.

"I'm not hungry."

"At least try to rest."

"Maybe later. Think I'll wander in and see how Bickel and Tim're doing." She looked at the big screen overhead. It was tuned to the peak-corner lenses of the computer shop.

"We have to have a constant monitor on each other," Timberlake had argued. "We can't wait for somebody to yell help."

The screen showed Bickel alone in the shop, but another eye had been keyed; it showed Timberlake asleep in his cubby adjoining the shop.

Four hours on and four hours off plus this constant looking over each other's shoulders will have us batty in a week, she thought.

Bickel looked up to his own screen-eye, saw Prudence watching, said: "Satan finds mischief for idle hands."

They mock me, Flattery thought. They laugh at God, at the Devil, at me.

"How about some coffee?" Prudence asked, speaking to Bickel.

"Coffee later," he said. "No more food of any kind in here, anyway. We have to keep the cover plates open and we can't risk contaminating the fine structure. If you're free, I could use some help."

She took one low-grav step across to the hatch lock, let herself through, stopped just inside the shop to study what Tim and Bickel had accomplished since her last free period.

Where the optical character reader had been, on the big panel across from the lock, now stretched a mechanical excrescence...iled and jutting structure of plastic blocks: Eng multiplier circuits, each sealed in plastic insulator. Linking the blocks were loops and tangles and twists -a black spiderweb of insulated pseudoneuron fiber.

Bickel had heard her entrance. Without turning from his work at one end of that protruding angular construction, he said: "Take that other micro-tie viewer on the bench. I need 21.006 centimeters of the K-A4 neurofiber with random-spaced endbulbs and multisynapses. Connect it as I've indicated on that schematic labeled G-20. It should be the top one in that pile on the right end of the bench."

Bickel sat down on the deck, slid a new block of Eng multipliers into position. He swung a portable micro-tie viewer across the block, leaned into the viewer's forehead rests, began making the connections.

Yes, sir! she thought.

She found the indicated schematic, reeled off the neurofiber, fed it into the viewer, bent to the eyepiece. The enlarged image of the conductor line with its green-coded synapse sections and yellow endbulbs leaped into view. She looked once more at the schematic, began making the required connections.

"What're we doing now, boss?" she asked.

"Installing a system of roulette cycles," Bickel said.

"Why?"

"A machine can reproduce any form of behavior," Bickel said. "We can engineer this device to satisfy any given input-output specifications. It'll behave anyway we want under any specified circumstances. "Raj set me straight on that."

She kept her tone light. "That was wrong, huh?"

"You bet your sweet life. Specified environment and behavior - that's deterministic. The manufacturer is still in control. What's worse, it requires a completely detailed memory - everything in the machine's past has to be immediate... right there and now! Memory load gets bigger and bigger every second. And it's all present and immediate. And that throws you into an infinite-design problem."

She reeled off a required length of side fiber, made the loop indicated in the schematic. "Infinite design. That means an indeterminate form and, by definition, the indeterminate is impossible to construct. So what do we do now?"

"Don't be dull," Bickel said. "We build for a random inhibitory pattern in the net - behavior that follows probability requirements." He leaned back from his viewer, wiped perspiration from his forehead. "A behavior pattern that results from built-in misfunction."

The way this ship was programmed to behave for us, she thought.

"Deterministic behavior from unreliable elements," she said. And she sensed Flattery's hand in this, an argument, a gentle nudge.

"Bickel," she said, "I've been stewing about your suspicions. Even if you're right - about one of us being set to blow us up if we go sour - how can you be sure this failsafe person is still among us? I mean, three of the original crew are dead."

"Okay," Bickel said. "Let's say we brought you out of hyb and you found our chaplain-psychiatrist had been killed. What were your orders?"

"Orders?"

"Come off that! We all had special orders."

"I'd have insisted we bring another chaplain-psychiatrist out of hyb," she said in a small voice. "What would you have done?"

"I had my orders, same as you."

She looked up at Flattery visible on the overhead screen. He appeared intent on the big board, paying no attention to the conversation coming over the intercom from the shop. That was sham, she knew. Everything said here was going into his brain, being weighed and analyzed.

Bickel's right, she thought. It's Raj.

"Pay attention to what you're doing!" Bickel said.

She turned, saw him watching her.

"You foul up the ties on that loop and I'll put you back in hyb," he said.

"Don't make threats you can't carry out," she said. But she turned back to the micro-tie viewer, finished off an inter-ringed series of loops, tested to be sure they weren't mutually oscillating, traced the output sheaf, and attached a plug for an Eng multiplier connection.

"Let me have that G-20 assembly as soon as you're finished," Bickel said. He yawned, put his knuckles to his eyes.

Prudence checked her assembly against the schematic, saw it matched, lifted it gently out of the viewer and took it to Bickel. He was overdue for a rest and still driving himself, she saw.

"Here," she said, presenting the assembly. "When you get this tied in, why don't you take a break."

"We're almost ready to put this on an initial program," Bickel said. He took the assembly, began connecting it to the newly installed Eng multiplier block, running one sheaf back to a plugboard connection on the computer panel.

Prudence stepped back, studied the mechanical growth that jutted from the wall. As though she saw it for the first time, the construction abruptly took on a new meaning for her.

"That's more than a setup for analysis," she said.

"That's right."

Bickel stood up, wiped his hands on the sides of his vacsuit, swung his own micro-manipulator and viewer to one side.

"This, in addition to giving us our analysis of built-in misfunction, this little 'Ox' we're driving will provide a three-way energy interchange."

"You're tied into the computer," she accused, pointing to the connections in the plugboard.

"Every line in that board has a diode in it. Pulses can come from the computer to our test setup, but anything going into the computer has to be coded by one of us and inserted over there." Bickel pointed to the input heads lined up at the right corner of the wall.

"Three-way interchange?" she asked.

"We're going to test my field-theory approach. I have a source program ready to insert. If our Ox doesn't work, it'll just produce an unconditional transfer of the material at the readout. If the field is produced, it'll act as a filter, and we'll get truncation. It'll pass only the significant digits."

"What about the roulette cycles?"

"The zero suppress will be intermittent," he said, "but we'll still get only the significant digits at the readout."

Prudence nodded, looking at Bickel with a new understanding of what he was doing: "All sense data are intermittent into the human consciousness."

It was an explosive thought: Wave forms! Everything which consciousness could identify had to move in some organized way. It had to move against a background which set off... which outlined!... the organization. Therefore: intermittence. And Bickel had seen right through to this necessity.

She found the realization somehow deeply sexual, and awareness of this filled her with disquiet. There was no way she could include anti-S on her present testing regimen. She wondered if her body might finally betray her.

Forcing herself to a calmness which she did not feel, she said: "What we see and identify has to be discrete and significant, it has to dance against some other background."

"Now you have it," Bickel said. "But we assume that the one who views the data is continuous...low of consciousness. Somewhere inside us, the discrete becomes amorphous. Consciousness weeds out the insignificant, focuses only on the significant."

"That's judgment," she said, "and it's where physicalist theory falls flat on its face. If this is an introspection device, then it won't be conscious. Introspection confuses consciousness with thinking. But sensing, feeling and thinking are physiological processes... and consciousness -"

"Is something else," Bickel said. "It's a relationship, a field; a selective interchange. It drops the insignificant digits. It's a weeder. Now, we see if we have a device that can weed on the basis of intermittent data, some of which is erroneous."

"Erroneous data - significant results," she whispered.

"What?"

But she ignored Bickel to turn and look at the overhead screen where Flattery was revealed calmly monitoring the big board. Something Flattery had said came now into her mind as though it had been amplified to full volume:

"There's nothing concerning ourselves about which we can be truly objective except our physical responses - the reflections of behavior. We exist in a forest of illusion where the very concept of consciousness merges with illusion. "

She turned to look at Bickel where he worked, seeing the stretch of his muscles under the vacsuit fabric as he bent to finish the assembly. And she thought: To be conscious, you must surmount illusion. Bickel saw that where I didn't.

A moment of illumination filled her mind and she saw the man at his work as more than flesh and sinew and nerves - more than the physical chemistry with blanks to be filled in. Bickel was both a minuscule and vulnerable creature, but beyond that, he contained powers that could stretch across any universe. Something of this momentary understanding struck her as almost religious... holy. She savored it, realizing this was a private and personal thing she could never completely communicate to another creature.

Bickel finished the final tie of the G-20 assembly, stood up, and rubbed the small of his back. His hands trembled as he relaxed after the fierce concentration of the work he had just completed.

"Let's give it a run," he said. "Prue, you monitor the diagnostic board." He gestured to the panel of dials and gauges waiting like so many glistening eyes at his left. "I'll give each net of the roulette cycles a one-fifth-second burst from the shot generator." He moved around to the right of the piled blocks of the test setup, stepping over the leads with elaborate care. He flipped the row of switches to start the source program through the inputs.

"Mark," he said.

"Mark," she said as her dial needles snapped over to register the pulse.

"Give me the mean synapse threshold, mean endbulb threshold, and action time on each net." Bickel depressed three switches simultaneously. "Interchange activated."

He waited, feeling the suspense grow, a tightness in his stomach.

"Interchange now showing entrance pulse," she said.

"Net one," he said, introducing the timed burst from the shot generator.

"There's a jam-up at the fifth-layer nodes," she said. She concentrated on the gauges for the fifth layer as though her thoughts could activate them, but they remained at zero. "No impulses are getting through," she said.

"I'll try sweeping the roulette cycles," Bickel said. He twisted a dial.

"Nothing," she said.

Bickel kicked off his row of switches, moved the jacks to the left. "Here, let's try a trigonometrically oscillating potential in the loops. Give me the new readings for each layer of the nets. Mark one."

"You're getting a nonlinear reaction across all the nets now," she said. "It's close to zero linearity."

"That can't be!" Bickel said. "These things are still open circuits no matter what we call them." He depressed another switch. "Read the other nets."

Prudence suppressed a sense of frustration, swept her gaze across the dials.

"Nonlinear," she said.

Bickel stepped back, glared at the input panel. "This is nuts! What we have here is essentially a transducer. The outputs should match!"

Again, Prudence read her dials. "Your products are still zero."

"Any heat?" Bickel asked.

"Nothing significant," she said.

Bickel pursed his lips, thinking. "Somehow, we've produced a unitary orthogonal system for each net and the total assembly," he said. "And that's a contradiction. It could mean we have more than one system in each of these separate nets."

"You have an unknown that's swallowing energy," Prudence said, her excitement kindling. "Isn't that our definition of -"

"It isn't conscious," Bickel said. "Whatever the unknown system is, it can't be conscious... not yet. This setup is too simple, doesn't have enough source data..."

"Then it's some error in the hookup," Prudence said.

Bickel's shoulders sagged. He took a deep, tired breath. "Yeah. Has to be."

"Where's your record of assembly and circuit tests?" Prudence asked.

"I isolated an auxiliary storage tank," Bickel said. He gestured vaguely to his left. "It's the red-flagged one. Everything's in there... including all this." He waved at the diagnostic panel.

"You get something to eat and take a rest break," she said. "I'll start tracing circuits."

"We got a jam-up on the direct test," Bickel said. "It wasn't an open-circuit reaction. And the net-interchange test produces zero at the output without flagging the point of loss. The thing's a goddamn sponge!"

"It'll be some simple error," she said. "Wake Tim and send him in while you're at it. He's had more than his four hours off."

"I am tired," Bickel admitted. He thought back, asking himself how long it had been since he had rested. Three full watches anyway.

I let myself get too tired, he thought. I know better. This is exacting work. Going too long without a break is the surest way to make mistakes.

"It'll be some simple thing," he said, but he knew as he said it that this was wrong. Sleep. He needed sleep.

Bickel headed toward quarters, pawing at the problem in his mind, rolling it over. The setup produced a contradictory reaction. Nothing simple was going to produce that complex a contradiction.

Behind him, Prudence activated the readouts at the red-flagged portion of the panel, started getting the feel of the setup. Sometimes with these computer problems, she knew, you could move intuitively into the area of difficulty, save yourself hours of hunting. Certain parts of a setup would feel wrong.

Presently, Timberlake joined her, yawning. "Bick told me. Trouble."

"Odd trouble."

"So I gathered." He cleared his throat. "Exactly what happened?"

She told him about the tests, the jam-up at the fifth-layer nodes and the subsequent disagreement between input and output.

"Zero linearity?" he asked.

"Almost."

"And no heat?"

"Nothing showed on the sensors."

Timberlake looked at the readout, the panel on both sides. "This is the storage tank we isolated. Have you examined the whole procedure?"

"I was just getting acquainted with the setup when you came in."

"That thing should've worked," Timberlake said. "It was a clean, straightforward construction all the way. I could've sworn it was going to give us that integrated readout, remove the nonsignificant digits, and we could just go on from..."

He paused, then said, "Unexpected feedback would... might cause the thing to react the way it did."

"I don't follow you."

"An oscillation. A flyback pulse that we didn't take into account."

"That might jam up the direct test," she said, "but it wouldn't account for the other reaction. If you were into the computer, of course... but that's one-way... isn't it?"

"Gated all the way. Our setup could receive selected data from the computer, but nothing went back in. No... I was thinking of this storage bank here." He nodded toward the panel in front of Prudence.

She turned toward the panel, puzzled. "But this is just......omplicated recorder. All it does is keep track of our work, step by step. It is isolated from the rest of the computer, isn't it?"

"What if it isn't isolated from the rest of the computer?" Timberlake asked.

"But Bickel assured me..."

"Yeah," Timberlake said, "and he probably believed it. I checked the work, too. If the schematics are correct, it's isolated. But what if the schematics are off?"

"Why would they be?"

"I don't know, but what if they are?"

Timberlake moved down the panel to the left, searching. He stopped at a translator output head. "Easy enough to find out. I'll just sort to find out if any of that test setup got into the master banks."

"If it did get in, there's no telling what it loused up," she said.

"Not necessarily," Timberlake said. He began cutting a program tape, referring to the computer banks themselves for the necessary data. Presently, he said, "That should do it."

Within seconds the load-and-go signal flashed at the readout in front of Timberlake. He switched it for an online printout and began reading the automatic translation.

"That was awfully fast," Prudence said.

Timberlake ignored her, scanning the tape as it chattered from the printer.

"For Chrissakes!" he said.

"What is it?" she asked, suppressing an irrational surge of fear.

"Get Bickel," Timberlake said. "This damn thing is giving us the truncated readout right here."

"What?"

"The answer we expected to get back at that setup if it worked," Timberlake said. "We're getting it here right now!"

"That's impossible," she said.

"Sure it is," Timberlake said. "You helped program this thing; look for yourself."

He whirled, brushed past her and headed for quarters. Prudence bent over the printout, scanned the selected bits, recognizing some of the math she had worked into the program for Bickel.

With a breath-stopping sense of awe, she realized that the printout was devoid of insignificant digits. It had been weeded down to essentials.