Brentano’s theory of value, derived from his philosophical psychology, is a theory of intrinsic value, that is, of what is good or bad in and of itself, not merely as a means to an end. Though Brentano’s attention to theoretical ethics took precedence over his practical ethics, the fundamentals of a system of practical or normative ethics are outlined in both The Origin of Our Knowledge of Right and Wrong (Brentano 1889/1969) and The Foundation and Construction of Ethics (Brentano 1952/1973b). In these works, the one supreme imperative upon which all others depend, referred to by Brentano as the “principle of the summation of good,” is that one should further the good in as wide a sphere as possible.