"Symposium" is not, after all, a modern Platonic dialogue. It is, rather, a murder mystery, but a mild one, in that neither victim nor suspects are emotionally engaging enough to arouse fear. The plot seems a mere excuse for describing the dinner, and the dinner an excuse for delineating modern types.

the reader’s first (misleading) impression is of a disorienting randomness of focus. The book begins with an extended dialogue between two characters who all but vanish for the rest of the story, and it ends by dwelling on the grief of another character who has only appeared once before, in a short, digressive scene aboard an aeroplane, and whose connection with the mainstream of the novel’s events is made all the more tenuous when his tailpiece is narrated, uniquely, in the future tense. (Here, as in all her novels, Spark is very careful about tenses.) ... The elaborate structure of Symposium now allows its author to explore, with a convert’s temerity, the very nature of omniscience, be it divine or authorial: of the several Catholic characters in the novel, by far the most important – although there are only one or two misjudged moments of specific intrusion – is the distinctly inscrutable deity who narrates it with such energy and relish.