 Plutarch's ethical works include some of theoretical orientation (e.g. On Moral Virtue, which refutes the Stoic theory of virtue) and some of practical one (e.g. On Control of Anger, On Curiosity, How Could you Tell a Flatterer from a Friend), offering practical advice on how to attain virtue and build a good character. The tendency, however, to distinguish two altogether separate classes of ethical works (following Ziegler 1951, 768–825) is problematic given the considerable affinities between them, yet Plutarch does use different styles in them, presumably targeting different audiences (Van Hoof 2010, 264–265). Particularly representative of Plutarch's ethical views are the treatises On Moral Virtue (De virtute morali), On Making Progress in Virtue (De profectibus in virtute), On Delays in Divine Punishment (De sera numinis vindicta), On Control of Anger (De cohibenda ira), and On Tranquility of Mind (De tranquillitate animi). Plutarch wrote also works on aesthetics and education, which one could classify also as works of practical orientation. Plutarch, following Plato, evaluates poetry from the point of view of ethical education. In this category belong the works On How the Young Man Should Listen to Poets (De audiendis poetis) and On the Education of Children (De liberis educandis), the latter of dubious authenticity (Ziegler 1951, 809–811).