"It sounds impressive," Greg said. "And you can use it to install new behaviour patterns as well?"

"Behaviour is rooted in memory, Mr Mandel. Conditioning again. You fall into a pool when you are a young child, nearly drowning; and in adult life you are wary of water, a poor swimmer, nor do you have any enthusiasm to improve. It is these countless cumulative small events and incidents in your formative years which decide the composition of your psyche. You are a soldier, I believe, Mr Mandel?"

"Was a soldier. I'm retired now."

"You volunteered for the army?"

"Yeah."

"And were you any good as a soldier?"

Greg shifted his weight on the settee's amorphous cushioning, conscious of Stephanie's stare. "I was mentioned in dispatches once or twice."

"And yet thousands, hundreds of thousands, of men your age were totally unsuitable for the military life you excelled in. Physically no different, but mentally, in outlook, your exact opposite. The respective attitudes both determined in the period between your fourth and sixteenth birthdays. We are what we are because of that time, the child being the father of the man. And that is the time we must alter in order to eradicate real-time psychoses. My aim is to substitute false paradigmatic memories for real recollections, thus effecting a radical change of temperament."

"Have you had any success?"

"Limited, but most promising given we have only been here two years. We have already succeeded in assembling some highly realistic synthetic memories. There is one, a walk through a forest." He closed his eyes and the eagerness and tension which had built up as he spoke drained out of his face, leaving him strangely peaceful. Almost the same expression as a synthohead, Greg thought.

"I can see the trees," MacLennan said, his voice reduced to a placid lilt. "They are large, tall as well as broad, in full leaf, oaks and elms. This is pre-Warming, midsummer, with sunbeams breaking through the overhead branches. I can see a squirrel, a red one; he's racing up an oak, round and round the trunk. I'm standing below watching him, touching the bark. It's rough, crinkled, dusted with a powdery green algae. The grass is ankle-high, dewy, wetting my shoes. There are foxgloves everywhere, and weasel-snout; I can smell honeysuckle."

"Lasers can imprint a smell?" Greg asked sceptically.

"The memory of a smell," Stephanie said pedantically. "We adapted the paradigm from a high-definition virtual reality simulation, then added tactile and olfactory senses, as well as emotional responses."

"Emotional responses?"

"Yes. Interpretation is a strong part of memory. if you see a particularly beautiful flower in the forest, you feel good about it; tread in a dog turd on the path, and you're disgusted."

Greg thought about it. He couldn't fault the logic, it was just that the whole concept seemed somewhat fanciful. But someone on the Berkeley board obviously had enough faith to invest in it. Quite heavily, judging by the facilities the Centre offered.

"Have you received this memory as well?" he asked her.

"Yes. It's very realistic. It feels like I was actually in that forest. James forgot to mention the birdsong. The thrushes are warbling the whole time."

Greg turned back to MacLennan, who was watching him levelly.

"How does this help to cure axe murderers?" Greg asked.

"Imagine when you were young if you took that same walk through a tranquil forest for half an hour instead of having to endure your drunken father beating you. If you had that walk, or played football, every evening he came home drunk; if you could remember your mother giving him a kiss instead of crying and screaming for mercy, I think you'd find your outlook on life would be very different."

"Yeah, and is it going to be possible?"

"I believe so. Once we have solved the problem of how to erase, or at the very least weaken, old memories. This is the area of research which requires the most effort in order for the project to succeed. Neurology and psychology to date have concentrated on memory recovery, helping amnesic victims, developing hypnotic recall techniques for vital witnesses, even preserving memories in the face of encroaching senility. The only comparable work in the opposing direction is with drugs which induce a form of transient amnesia, like scopolamine. These are no use to us, as they only prevent memories from being retained while the drug is in effect. What we need is something which will go into a subject's mind and hunt down the original poisonous memories."

"Sounds like a job for a psychic," Greg said.

"It's an option we've considered. In fact it was one reason I was particularly delighted when I was informed you would be coming today. I wanted to quiz you on the parameters of psi. The Home Office said you were one of the best ESP-orientated psychics to emerge from the Mindstar project. Are you able to interpret individual memories?"

"No. Sorry, I'm strictly an empath."

"I see." He clasped his hands together and rested his chin on the knuckles. "Do you know of any psychic who can do that?"

"There were a couple in Mindstar who had the kind of ability you're talking about. They used to be able to lift faces and locations out of a suspect's thoughts." He almost said prisoner, but with Stephanie leaning forward in her seat, hanging on to every word, that would never do. He wanted her wholehearted co-operation. "I don't think they could perform anything like the deep-ranging exploration you require."

"That's a pity," MacLennan said. "I might apply for a licence to practise with a themed neurohormone if one could be developed along those lines."

"Are you completely stonewalled without psychic analysis?"

"No. There are several avenues we can pursue. Paradigms could be structured to wipe selected memories. A sort of anti-memory, if you like. The major trouble is again one of identification. We need to know a memory in order to wipe it—the nature of it, the section of the brain where it is stored."

"A real-time brain scan might just tell us," Stephanie said. "If the subject recounts a particularly traumatic incident it may be possible to locate the specific neurons which house it. The erasure paradigm could then be targeted directly at them. Magic photons, we call it, after the magic bullet; like cancer treatments which kill tumour cells without harming the ordinary cells around it."

"You would need some very sophisticated sensors to scan a brain that accurately," Greg pointed out. "Not to mention processing capacity. Part of my psi-assessment tests involved a SQUID scan, but there was no way you could get the focus fine enough to resolve individual neuron cells."

"Berkeley has allocated us considerable resources," MacLennan said. His chirpy everything-under-control smile had returned. "We have one SQUID brain scanner already installed here at the Centre. Although, admittedly, its resolution does fall some way short of the requirement Stephanie envisages for the magic photons concept to function. But it is a modest first step. And several medical equipment companies are working on models which offer a higher resolution. I have high hopes for the project."

"This paradigm research is an expensive venture," Greg said. "The Board must have a lot of faith in you."

"They do. I didn't promise them instant results and success. They fully understand that it is a medium-term project, commercial viability will not be realized for at least another seven to ten years. But they agreed to back it because of the potential. You see, if paradigm-based treatment does work, it will revolutionize the entire penal system. We would have to rebuild our institutions from the ground up. The only people who will actually require detention are petty criminals, everyone else will be reformed in medical facilities."