Having, by the strict criterion of published work, been mathematically inactive for more than twenty years, Petros was now academically unemployable and so he had to return to his homeland. During the first years of the country's occupation by the Axis powers he lived in the family house in central Athens, on Queen Sophia Avenue, with his recently widowed father and his newly-wed brother Anargyros (my parents had moved to their own house), devoting practically all his time to chess. Very soon, however, my newborn cousins with their cries and toddler activities became a much greater annoyance to him than the occupying Fascists and Nazis and he moved to the small, rarely used family cottage in Ekali.

After the Liberation, my grandfather managed to secure for Petros the offer of the Chair of Analysis at Athens University, through string-pulling and manoeuvring. He turned it down, however, using the spurious excuse that 'it would interfere with his research'. (In this instance, my friend Sammy's theory of Goldbach's Conjecture as my uncle's pretext for idleness proved completely correct.) Two years later, paterfamilias Papachristos died, leaving to his three sons equal shares of his business and the principal executive positions exclusively to my father and Anargyros. 'My eldest, Petros,’ his will expressly decreed, 'shall retain the privilege of pursuing his important mathematical research,’ i.e. the privilege of being supported by his brothers without doing any work.

'And after that?' I asked, still cherishing the hope that a surprise might be in store, an unexpected reversal on the last page.

'After that nothing,’ my uncle concluded. ‘For almost twenty years my life has been as you know it: chess and gardening, gardening and chess. Oh, and once a month a visit to the philanthropic Institution founded by your grandfather, to help them with the book-keeping. It's something towards the salvation of my soul, just in case there exists a hereafter.'

It was midnight by this time and I was exhausted. Still, I thought I should end the evening on a positive note and, after a big yawn and a stretch, I said: 'You are admirable, Uncle… if not for anything eise, for the courage and magnanimity with which you accepted failure.'

This comment, however, got a reaction of utter surprise. 'What are you talking about?' my uncle said. 'I didn't fail!'

Now the surprise was mine. 'You didn't?'

'Oh no, no, no, dear boy!' He shook his head from side to side. 'I see you didn't understand anything. I didn't fail – I was just unlucky!'

'Unlucky? You mean unlucky to have chosen such a difficult problem?'

'No,’ he said, now looking totally amazed at my inability to grasp an obvious point. 'Unlucky – that, by the way, is a mild word for it – to have chosen a problem that had no solution. Weren't you listening?' He sighed heavily. 'By and by, my suspicions were confirmed: Goldbach's Conjecture is unprovable!'

'But how can you be so sure about it?' I asked.

'Intuition,’ he answered with a shrug. 'It is the only tool left to the mathematidan in the absence of proof. For a truth to be so fundamental, so simple to state, and yet so unimaginably resistant to any form of systematic reasoning, there could have been no other explanation. Unbeknown to me I had undertaken a Sisyphean task.'

I frowned. 'I don't know about that,’ I said. 'But the way I see it -'

Now, however, Uncle Petros interrupted me with a laugh. 'You may be a bright boy,’ he said, but mathematically you are still no more than a foetus – whereas I, in my time, was a veritable, full-blown giant. So, don't go weighing your intuition against mine, most favoured of nephews!' Against that, of course, I couldn't argue.

My first reaction to this extensive autobiographical account was one of admiration. Uncle Petros had given me the facts of his life with remarkable honesty. It wasn't until a few days later, when the oppressive influence of his melancholy narrative diminished, that I realized everything he'd told me had been beside the point.

Remember that our meeting had been initially arranged so that he could try to justify himself. His life's story was only relevant to the extent that it explained his atrocious behaviour, assigning me in all my adolescent mathematical innocence the task of proving Goldbach's Conjecture. Yet, during his long narrative he had not even touched on his cruel prank. He'd ranted on and on about his own failure (or maybe I should do him the favour of calling it 'bad luck'), but about his decision to turn me away from studying mathematics and the method he had chosen to implement it, not a single word. Did he expect me automatically to draw the conclusion that his behaviour to me was determined by his own bitter life-experiences? It didn't follow: although his life story was indeed a valid cautionary tale, it taught a future mathematician what pitfalls to avoid so as to make the most of his career – not how to terminate it.

I let a few days go by before I went back to Ekali and asked him point-blank: could he now explain why he had attempted to dissuade me from following my inclination.

Uncle Petros shrugged. 'Do you want the truth?'

'Of course, Uncle.' I said. 'What eise?'

'All right then. I believed from the first moment – and still do, I'm sorry to say – that you have no special gift for great mathematics.'

I became, once again, furious. 'Oh? And how on earth could you have known that? Did you ask me a single mathematical question? Did you ever set me a problem to solve, other than the unprovable, as you termed it, Conjecture of Christian Goldbach? I certainly hope you don't have the nerve to tell me that you deduced my lack of mathematical ability from that!'

He smiled, sadly. 'You know the popular saying that the three conditions impossible to conceal are a cough, wealth and being in love? Well, to me there is a fourth: mathematical gift.'

I laughed contemptuously. 'Oh, and you can no doubt identify it at a glance, eh? Is it a look in the eye or a certain je ne sais quoi that betrays to your ultra-fine sensibility the presence of mathematical genius? Can you perhaps also determine one's IQ with a hand-shake?'

'Actually there is an element of that "look in the eye",’ he replied, ignoring my sarcasm. 'But in your case physiognomy was only a small part of it. The necessary – but not sufficient, mind you – precondition for supreme achievement is single-minded devotion. If you had the gift that you yourself would like to have had, dear boy, you wouldn't have come asking for my blessing to study mathematics; you would have gone ahead and done it. That was the first tell-tale sign!'

The more he explained himself, the angrier I got. 'If you were so certain I wasn't gifted, Uncle, why did you put me through the horrific experience of that summer? Why did I have to be subjected to the totally unnecessary hurmliation of thinking myself a near-idiot?'

'But, don't you see?' he answered merrily. 'Goldbach's Conjecture was my security! If by some remote chance I'd been wrong about you and, in the most unlikely instance, you were indeed earmarked for greatness, then the experience wouldn't have crushed you. In fact it would not have been at all "horrific", as you significantly termed it, but exciting and inspiring and invigorating. I gave you an ultimate trial of determination, you see: if, after failing to solve the problem I'd set you – as, of course, I knew you would – you came back eager to learn more, to persist in your attempt for better or for worse, then I'd see you might have it in you to become a mathematician. But you… you weren't even curious enough to ask the solution! Indeed, you even gave me a signed declaration of your incompetence!'

The pent-up anger of many years now exploded. 'Do you know something, you old bastard? You may once have been a good mathematician, but as a human being you rate zero! Absolutely, totally zilch!'