In the first part (chapters 1-8), the author demonstrates through the authoritarian voice of his own father that the Stoics, in so far as they affirm the irrationality of animals, contradict their own tenets. The second part proves that animals of all kinds are rational (chapters 9-36); the last small section, while refusing to award first honours in the debate, appears to contain Plutarch’s exhortation to his pupils to continue the fight against the Stoics. For an excellent summary with sympathetic comments see E. R. Dodds, Greece and Rome, ii (1932/3), pp. 104-105.
