Talking to oneself is not respectable. It suggests many things, none of them good: abysmal loneliness, a mental screw loose, a social wire frayed, insanity, dementia. Shukan Post magazine this month cites experts in dementia who see solitary dialogue as a potential premonitory sign — not a conclusive one, but one that bears watching, as a symptom or a cause of a descent into a place we'd all rather avoid, from which few return alive.