  It is important here to note the distinction between theoretical and practical authority. A theoretical authority in some area of intellectual inquiry is one that is an expert in that area. Theoretical authorities operate primarily by giving advice to the layman, which advice the layman is free to take or not. The judgments of theoretical authorities give people reasons for belief while the judgments of political authorities are normally thought to give people reasons for action. Theoretical authorities do not normally impose duties on others, although they might give advice on what a person's duty is.