ought to do, in those cases and those cases only, where there happens to be only one which is right under the circumstances—where, that is to say, there are not several which would all be equally right, but some one of the alternatives open to us is the only right thing to do. And hence in many cases we cannot definitely say of a voluntary action either that it was the agent’s duty to do it nor yet that it was his duty not to do it. There may be cases in which none of the alternatives open to us is definitely prescribed by duty.
To sum up, then: The answers which this theory gives to its first set of questions is as follows. A characteristic which belongs to all right voluntary actions, and only to those which are right, is, it says, this: That they all cause at least as much pleasure as any action which the agent could have done instead; or, in other words, they all produce a maximum of pleasure. A characteristic which belongs to all voluntary actions, which ought to be done or which it is our duty to do, and only to these, is, it says, the slightly different one: That they all cause more pleasure than any which the