‘We could get an ice-cream across the road.’

‘Great idea. As long as they’ve got apricot.’

I assessed that I was progressing well at this point, and did not think the apricot preference would be a problem. I was wrong. The ice-cream parlour had a vast selection of flavours, but they had exhausted their supply of apricot. I ordered a chocolate chilli and liquorice double cone for myself and asked Elizabeth to nominate her second preference.

‘If they haven’t got apricot, I’ll pass.’

I couldn’t believe it. All ice-cream tastes essentially the same, due to chilling of the tastebuds. This is especially true of fruit flavours. I suggested mango.

‘No thanks, I’m fine.’

I explained the physiology of tastebud chilling in some detail. I predicted that if I purchased a mango and a peach ice-cream she would be incapable of differentiating. And, by extension, either would be equivalent to apricot.

‘They’re completely different,’ she said. ‘If you can’t tell mango from peach, that’s your problem.’

Now we had a simple objective disagreement that could readily be resolved experimentally. I ordered a minimum-size ice-cream in each of the two flavours. But by the time the serving person had prepared them, and I turned to ask Elizabeth to close her eyes for the experiment, she had gone. So much for ‘evidence-based’. And for computer ‘scientist’.

Afterwards, Claudia advised me that I should have abandoned the experiment prior to Elizabeth leaving. Obviously. But at what point? Where was the signal? These are the subtleties I fail to see. But I also fail to see why heightened sensitivity to obscure cues about ice-cream flavours should be a prerequisite for being someone’s partner. It seems reasonable to assume that some women do not require this. Unfortunately, the process of finding them is impossibly inefficient. The Apricot Ice-cream Disaster had cost a whole evening of my life, compensated for only by the information about simulation algorithms.

Two lunchtimes were sufficient to research and prepare my lecture on Asperger’s syndrome, without sacrificing nourishment, thanks to the provision of Wi-Fi in the medical library café. I had no previous knowledge of autism spectrum disorders, as they were outside my specialty. The subject was fascinating. It seemed appropriate to focus on the genetic aspects of the syndrome, which might be unfamiliar to my audience. Most diseases have some basis in our DNA, though in many cases we have yet to discover it. My own work focuses on genetic predisposition to cirrhosis of the liver. Much of my working time is devoted to getting mice drunk.

Naturally, the books and research papers described the symptoms of Asperger’s syndrome, and I formed a provisional conclusion that most of these were simply variations in human brain function that had been inappropriately medicalised because they did not fit social norms – constructed social norms – that reflected the most common human configurations rather than the full range.

The lecture was scheduled for 7.00 p.m. at an inner-suburban school. I estimated the cycle ride at twelve minutes, and allowed three minutes to boot my computer and connect it to the projector.

I arrived on schedule at 6.57 p.m., having let Eva, the short-skirted cleaner, into my apartment twenty-seven minutes earlier. There were approximately twenty-five people milling around the door and the front of the classroom, but I immediately recognised Julie, the convenor, from Gene’s description: ‘blonde with big tits’. In fact, her breasts were probably no more than one and a half standard deviations from the mean size for her body weight, and hardly a remarkable identifying feature. It was more a question of elevation and exposure, as a result of her choice of costume, which seemed perfectly practical for a hot January evening.

I may have spent too long verifying her identity, as she looked at me strangely.

‘You must be Julie,’ I said.

‘Can I help you?’

Good. A practical person. ‘Yes, direct me to the VGA cable. Please.’

‘Oh,’ she said. ‘You must be Professor Tillman. I’m so glad you could make it.’

She extended her hand but I waved it away. ‘The VGA cable, please. It’s 6.58.’

‘Relax,’ she said. ‘We never start before 7.15. Would you like a coffee?’

Why do people value others’ time so little? Now we would have the inevitable small talk. I could have spent fifteen minutes at home practising aikido.

I had been focusing on Julie and the screen at the front of the room. Now I looked around and realised that I had failed to observe nineteen people. They were children, predominantly male, sitting at desks. Presumably these were the victims of Asperger’s syndrome. Almost all of the literature focuses on children.

Despite their affliction, they were making better use of their time than their parents, who were chattering aimlessly. Most were operating portable computing devices. I guessed their ages as between eight and thirteen. I hoped they had been paying attention in their science classes, as my material assumed a working knowledge of organic chemistry and the structure of DNA.

I realised that I had failed to reply to the coffee question.

‘No.’

Unfortunately, because of the delay, Julie had forgotten the question. ‘No coffee,’ I explained. ‘I never drink coffee after 3.48 p.m. It interferes with sleep. Caffeine has a half-life of three to four hours, so it’s irresponsible serving coffee at 7.00 p.m. unless people are planning to stay awake until after midnight. Which doesn’t allow adequate sleep if they have a conventional job.’ I was trying to make use of the waiting time by offering practical advice, but it seemed that she preferred to discuss trivia.