The other day I met a man who claimed he could eat his own head. I considered this preposterous, and said so. We were at a sophisticated cocktail party and he was leaning insouciantly against a mantelpiece.

“I can prove it to you,” he said, “As a demonstration, I will eat your head, and that will show that I could eat my own.”

I thought about this for perhaps three seconds before responding.

“Your so-called proof has several distinct flaws,” I said, “First, that if you eat my head, I will be in no position to form a judgement on the success or otherwise of your antics, as I presume I will lose consciousness and die as you gnaw through my neck, thus severing those all-important nerves and arteries and whatnot that enable my brain to function. Second, your ability to eat my head has no bearing whatsoever on your claim to be able to eat your own head. It is an entirely different head.”

He took a sip of his cocktail before conceding.

“Those are both valid points. But there were but two, and you said you had several.”

“Let those two suffice for the time being,” I said.

“Very well,” he replied, “I can see that I am up against a sceptic of formidable mental acuity. You are not by any chance a Jesuit, are you?”

I assured him I was not, despite it having been a childhood ambition to be ordained into the order.

“I, too, once dreamed of becoming a Jesuit,” he said, “But alas, I lost my faith. Still, that was a long time ago, since when I suppose I learned to replace it with the more fervent belief that I can eat my own head. You will not be satisfied until you actually witness me in the act of doing so, will you?”

I nodded my agreement. He looked at me in silence, and after a pause, said “There”.

“There what?” I asked.

“I just ate my own head and regurgitated it, as a bird does with food for its young.” he said, “You must excuse my manners, for I am a terribly fast eater and tend to gobble my food. I can be quite a cause of social discomfiture in the better restaurants.”

“I witnessed neither eating nor regurgitation,” I said, “You just stood there looking at me.”

He sighed with a measure of impatience.

“I have just explained to you that I eat with regrettable speed,” he said, “And this habit has a deleterious effect on my digestive system, one consequence of which is that I cannot tolerate certain foodstuffs, including human flesh and bone and brain matter, etcetera, so I spew them up immediately.”

“You are a very foolish man. Good evening to you, sir,” I said, and I turned on my heel and wandered off across the room, away from the mantelpiece, in search of somebody else to talk to.

Later that evening, passing near the mantelpiece again, I saw the man biting the head off another party guest, a person who, I reasoned, had not had the benefits of a Jesuitical education, and thus could not counter the arguments of this foolish but persuasive fellow. There was blood on the carpet, as there so often is, even at the most sophisticated cocktail parties.