 His "Compendium ethicae Aristotelicae" was based on courses at Middleburg school.In defining an eclectic moral philosophy that would nevertheless be acceptable to Christians, Walaeus chose the "Nicomachean Ethics" of Aristotle as a basis, to be corrected, despite a view that Plato was the superior moral philosopher as Aristotle was the better physicist; he used Aristotle's classification of virtues rather than the Protestant Lambert Daneau's reliance on the Ten Commandments.Plato's purifying virtues were matched to the account in the Beatitudes; but in the end Plato was found to lack Christian theological concepts.