contact. When a lion sees a zebra, the lion doesn't forget where the zebra is when it looks away momentarily. Your computer works the same way.'
Laura assumed they probably already knew what she'd just reported, but her 'teammates' refrained from deriding her this time. That fact buoyed her — made her feel a more qualified member of the team. 'So,' an emboldened Laura said in the silence, 'how goes the effort to load that antiviral program?'
Filatov shrugged. 'We've cut way down on system maintenance and are leasing third-party computers to off- load operations. We hope to free up enough capacity to try the phase-two again sometime tonight.'
'Any new ideas about what's wrong with the computer?' Laura asked in between bites of her sandwich.
'We have competing theories in play,' Gray answered. 'Mr. Hoblenz believes we're being hit with penetration attempts by governmental or corporate intruders.' Hoblenz nodded.
'Dr. Bickham, however,' Gray continued, looking at Margaret, 'has raised the relatively frightening prospect of a malignant, mutant virus that evolved naturally from the computer's ecosystem.'
Laura was poised to take another bite of her sandwich, but she lowered it from her mouth and said, 'Whoa, whoa. What did you just say?'
'Do you know what genetic algorithms are?' Gray asked.
Laura hesitated. 'If I say no, am I gonna get a long lecture?'
Hoblenz laughed in a low and raspy voice. The only other person at the table to smile was Gray. 'Well, it's important for your work that you know.' Laura sighed and nodded. She sank back into her chair and crossed her arms over her chest.
'We've achieved three breakthroughs in natural computation that have allowed us to build an intelligent computer. The first was the architecture — a true neural network. The second was successfully programming into the computer the rules of fuzzy logic and chaos theory, which allow the computer to predict what was previously thought to be unpredictable. But the third was our use of genetic algorithms, which was by far the most important advance. Have you ever read
Laura was taken aback. 'Do you mean Charles Darwin's treatise on evolution?' she asked, and Gray nodded. 'Well, I've never actually read it, no.'
'You should. It's the single greatest intellectual accomplishment in man's history.' Laura arched her brow in surprise and looked at her colleagues around the table. They remained silent and deferential during Gray's lecture. 'Genetic algorithms are a way of using Darwin's theories of evolution to program a computer to solve problems. In nature, the more fit an organism is, the more likely it is to pass on its genes. New organisms are evaluated harshly. The winners live and pass on their traits, the losers die. The system doesn't care what characteristics get handed down. By the mere act of survival, the organism has proved its superiority.'
Gray seemed totally focused on her, concentrating on making himself understood as if her comprehension were of the utmost importance.
'We have instituted Darwin's rules of natural selection inside the computer,' he said, his words spoken with such care that they possessed a gravity that fully captured Laura's attention. 'Instead of organisms competing for survival, we have computer programs. Instead of passing genes on to their descendants, the programs that survive pass on the superior computer codes they use to solve problems. Their fitness is evaluated by how much those programs' solutions contribute to optimal computer performance. Programs that do poorly get eliminated from the gene pool. Programs that produce good results live on, and every so often they combine with other survivors. The new programs are sometimes defective, but other times they use novel approaches to arrive at truly unique solutions. That's why this computer has what no other has had before — brilliance. And the system works, Dr. Aldridge, only by strict adherence to the rules of natural selection. Only by pure survival of the fittest.'
Laura felt, as always, out of her depth. 'How in the world do you program a computer to operate like that?'
Margaret answered from her accustomed place to Gray's left. 'Whenever there's a new problem, the computer mixes up a huge population of what we call 'chromosomes.' They're just tiny strings of connection sets — computer programs — that take data as their input and output a guess as to what the answer is. Genetic algorithms manage the whole process. The algorithm's selection operator chooses which chromosomes are most fit and mates them. That forms new and generally more sophisticated offspring programs that are then evaluated for mating on the basis of their fitness, et cetera, et cetera.'
Dorothy picked up the thread. 'That's how we think a virus might have naturally arisen. You see, it's important to preserve the diversity of the population. The genetic algorithm has to maintain a fine balance. If the programs get too inbred, they don't explore new problem-solving avenues. But if they mutate too often, it screws up the gradual improvement in the programming that natural selection gives you. So every once in a while, the genetic algorithm's mutation operator injects a random variable into the mix during the mating process. A different twist in the program's logic. I think what happened is that a mutant strain of highly capable chromosomes has developed and is at work in the system.'
Laura looked from face to face around the table. This was all so mundane to them, but it sounded impossibly complex to her.
'Shouldn't the antiviral program catch a mutant virus like that?' she asked. 'I mean, if it's causing all those errors…?'
Gray answered. 'The phase-one, two, and three don't just rid the system of foreign viruses, they're also the weapon used by the selection operator to cull the programs that are less fit. They are the enforcers of the strict laws of Darwinism. Two programs compete against each other, and the antiviral programs await the loser. Those are the rules of the system, Dr. Aldridge. That is the law.'
Gray seemed to wait for Laura to respond. When she didn't, he continued. 'It's harsh justice, I know, but you've seen what it has accomplished. We don't interfere with the selection process,' he stood making the point now to his still-silent department heads. 'We can't. That's an unwavering rule.'
'So why are you trying to manually load the phase-two?' Laura asked. 'Isn't that interfering with the selection process?'
Several heads shook all at once, but it was Dorothy who replied. 'The programs are hard to kill. They're meant to be robust, so they repel or flee from any reprogramming signals that might cause damage to their codes. Occasionally some are so good at survival that they avoid termination by the phase-one. They then become a 'virus.' And since this is a computer, those outbreaks can occur in just nanoseconds. That's why I programmed the phase-one to load the phase-two or — three automatically if the one's not up to the job.'
'Then why are you doing all this manually?' Laura persisted.
'Because when the phase-one can't identify and localize the virus for a quick kill by a clipped version of the phase-two, we've got to free up enough space to load the entire program. The full version of an antiviral program scans, analyzes, identifies, tracks, localizes, destroys, repairs, and reports. Each step is a massive program that itself evolved through natural selection, combined by mating, and survived by out-competing opponents. Luckily, we've only had one outbreak that required a full loading of the most capable of the antiviral programs.'
'The Hong Kong flu, or whatever you called it?' Laura asked.
Dorothy nodded, then fell silent. The mere mention of the episode seemed to cast a pall over the table.
Gray resumed the lecture. 'In the case of the Hong Kong 1085, we had to go to the phase-three. Since the kill time was going to be extended, we had to manually off-load operations just like we're trying to do today.' The strain showed on his face as he continued. 'You see, the phase-one, — two, and — three are each completely different. They evolved independently. The phase-three was the 'winner' of the competition. It's the best killer by far. But we kept all three because the more capable a killer they are, the more damage they cause in the process. The phase- three is like chemotherapy. We used it only as a last resort.' He looked now around the table. 'We were losing the system.' Everyone remained quiet. 'The phase-three doesn't tiptoe around like the phase-one, or even the — two. When the phase-three goes in, it goes in hard.'
'Slash and burn,' Margaret said with distaste.
'It saved the system!' Dorothy objected testily.
'It killed the virus,' Gray interjected, quieting the incipient debate. 'We had to shut down for several days to work around the damage. It was touch-and-go, but the computer was able to relearn most of what it had lost by analogy to the undamaged connections. But if we'd lost much more code, or if what we did lose had been of a more critical nature, the system might've been unrecoverable.'
The team remained quiet in the moments that followed. Most had sober looks on their faces.
