"The professional man lives off ideas, not for them. ... He has acquired a stock of mental skills that are for sale. The skills are highly developed, but we do not think of him as being an intellectual if certain qualities are missing from his work—disinterested intelligence, generalizing power, free speculation, fresh observation, creative novelty, radical criticism. At home he may happen to be an intellectual, but at his job he is a hired mental technician who uses his mind for the pursuit of externally determined ends. It is this element—the fact that ends are set from some interest or vantage point outside the intellectual process itself—which characterizes both the zealot, who lives obsessively for a single idea, and the mental technician, whose mind is used not for free speculation but for a salable end. The goal here is external and not self-determined, whereas the intellectual life has a certain spontaneous character and inner determination. It has also a peculiar poise of its own, which I believe is established by a balance between two basic qualities in the intellectual’s attitude toward ideas—qualities that may be designated as playfulness and piety."