Letters 29.6

He will bring to my notice Aristo, the philosopher of Marcus Lepidus, who used to hold discussions in his carriage; for that was the time which he had taken for editing his researches, so that Scaurus said of him when asked to what school he belonged: “At any rate, he isn’t one of the Walking Philosophers.” Julius Graecinus, too, a man of distinction, when asked for an opinion on the same point, replied: “I cannot tell you; for I don’t know what he does when dismounted,” as if the query referred to a chariot-gladiator.

Seneca, Letters to Lucilius 29.6, translated by Richard Mott Gummere