‘How’s what going?’ he replies, voice sharp. ‘My work? Or my marriage?’

I know I need to be patient with him until he forgives me. I take a deep breath. ‘Well everything I suppose.’

He takes a sip of whisky, leans back and crosses his legs. ‘As a matter of fact I’m working on vagueness, conditionals and supervaluationism at the moment.’

‘What’s that?’ I ask, feigning interest.

‘Are you sure you want to know?’

‘Try me.’

‘I’m arguing that vagueness produces counter-examples to modus tollens.’

‘Do I need to understand Latin now?’ I pause. ‘Is it even Latin? I don’t know.’

‘Of course it’s Latin. You studied it at Charterhouse.’

‘I took it for a few years, but it might as well have been Double Dutch to me.’

‘Well you are right, it is Latin.’ He pauses. ‘And modus tollens is a deductive argument form. And a rule of inference. Would you like me to explain?’

I do not want him to. But I so want to make friends with him again that I swallow and nod my head.

Miles continues, ‘This is how it works. “If P, then Q. Not Q. Therefore not P.” It is an application of the general truth that if a statement is true, then so is its contrapositive. The form shows that inference from “P implies Q” to “the negation of Q implies the negation of P” is a valid argument.’ He pauses. ‘Do you understand?’

‘You’re joking aren’t you? Trying to bait me? Trying to make me feel stupid.’

He uncrosses his legs, puts his whisky down on the table in front of him, and leans forwards. ‘I’m sorry. I didn’t mean to upset you. It’s so complicated I find it hard to explain.’

‘Philosophy makes my brain ache. It makes most people’s brains ache. But then you were always such an intellectual weren’t you? A cut above the rest.’ I pause. ‘And now you are a professor, you really need to learn how to explain things clearly.’

My voice is rising. I need to be careful. I invited him over to make friends, not to antagonise him.

He hesitates. ‘Sorry I expressed myself badly. I really wasn’t trying to score points against you.’

I smile uncertainly. ‘OK. Well let’s just start again.’ I pause. ‘What about the children? Why don’t you tell me about them? How they’re getting on?’

His eyes darken. ‘You see them every Sunday when you come for lunch.’

‘Stop being arsey. I invited you over because I want us to be friends again.’

‘You’ve always been my friend.’ Miles pauses, eyes full of sadness. ‘I just want you to stop flirting with my wife.’

I lift my shoulders and raise my palms to the ceiling. ‘I’ve apologised. I won’t do it again.’

He shakes his head. ‘I’m not sure I believe you.’