Odyssey 15.69-71 has Menelaus advise Telemachus that a host who loves or hates a guest to excess is worse than one who observes αἴσιμα (aisima; `due measure'), a word usually rendered as measure, balance or moderation. Read against the vocabulary of modern optimisation, the passage can look like an early statement of an optimisation principle: two extremes excluded, something better in between. We argue that this resemblance is misleading. The Greek text describes a tolerance interval, a set of acceptable conduct with no criterion for ranking one acceptable choice above another, rather than an interior extremum, a unique optimal point which, for a differentiable objective, is marked b... More >