“Thirteen, twelve—it is irrelevant! One asks a doctor, a medical expert: is it theoretically possible for a female of thirteen, or twelve, to give birth to a child? The answer is either yes or no. Please let us not debate the borderline cases of potential childbearing ages! Have you forgotten the other intriguing statement made by Samuel Kidd in connection with this allegedly younger man: ‘His mind? I’d argue he has no mind.’ No doubt you will say that Mr. Kidd meant nothing more than that the man in question was an imbecile.”

“No doubt I will,” I said peevishly. “Why don’t you tell me what I’m missing, since you’re so much cleverer than I am?”

Poirot made a dismissive clicking noise. “Sacré tonnerre. The couple under discussion in Room 317 were Harriet Sippel and her husband George. The conversation was not a serious debate—it was mockery. George Sippel died when he and Harriet were both very young. Samuel Kidd argues that he has no mind because, if George Sippel exists at all after his death, it is not in human form. He is a ghost, n’est-ce pas? Since the mind is inside the brain, and the soul does not possess human organs, George Sippel the ghost cannot have a mind.”

“I . . . Oh, heavens. Yes, now I see.”

“Samuel Kidd introduces his point of view in the way that he does—‘I would argue . . .’—because he expects Nancy Ducane to disagree. She might well have said, “Of course a ghost must have a mind. Ghosts have agency, do they not, and free will? From where do these things come if not the mind?”

Philosophically, it was an interesting point. In different circumstances, I could imagine taking a view on the matter myself.

Poirot continued: “Nancy’s ‘old-enough-to-be-his-mother’ remark was based on her belief that, when a man dies, his age is then fixed forevermore. In the afterlife, he does not age. George Sippel, if he were to return as a spirit to visit his widow, would be a young man in his twenties, the age he was when he died. And she, as a woman in her forties, is now old enough to be his mother.”

“Bravo,” said Jennie in a matter-of-fact tone of voice. “I was not there, but the conversation was continued later in my presence. Monsieur Poirot really is formidably perceptive, Mr. Catchpool. I hope you appreciate him.” To Poirot, she said, “The argument went on . . . oh, just for ever! Nancy insisted she was right, but Sam would not concede the point. He said ghosts do not exist in the dimension of age—they are timeless, so it is incorrect to say that anyone could be old enough to be a ghost’s mother.”