Men are too ignorant to fix their own ideas as the basis of all action.
Priestley could not escape entirely the bondage of past tradition; and the metaphysics which Bentham abhorred are scattered broadcast over his pages.

Nevertheless the basis upon which he defended his ideas was a utilitarianism hardly less complete than that which Bentham made the instrument of revolution.

"Regard to the general good," he says, "is the main method by which natural rights are to be defended." "The good and happiness of the members, that is, the majority of the members of any State, is the great standard by which everything relating to that state must finally be determined." In substance, that is to say, if not completely in theory, we pass with Priestley from arguments of right to those of expediency.

His chief attack upon religious legislation is similarly based upon considerations of policy.

His view of the individual as a never-ending source of fruitful innovation anticipates all the later Benthamite arguments about the well-spring of individual energy.