Michael Frayn has solved a problem for me. I am often asked to recommend a book that will get interested parties well into philosophy, and find myself at a stand because text-book introductions are typically flat-footed and simplistic, parcelling everything into over-neat isms, whereas the best introductions – the classics of philosophy themselves – are typically not approachable without help.

But here is a book by an author who tackles philosophical problems by thinking them through for himself intelligently and lucidly, who writes beautifully, and who conveys a living sense of the puzzling character of thought and the world that lies at the root of all genuine philosophising.

The result is impressive, and not because it is, like Dr Johnson’s dog walking on its hind legs, the effort of a gifted amateur who deserves a pat on the head. Far from it: Frayn studied philosophy at Cambridge, and in the midst of a busily successful career as novelist