Ethics, therefore, is quite unable to give us a list of duties: but there still remains a humbler task which may be possible for Practical Ethics. Although we cannot hope to discover which, in a given situation, is the best of all possible alternative actions, there may be some possibility of shewing which among the alternatives, _likely to occur to any one_, will produce the greatest sum of good. This second task is certainly all that Ethics can ever have accomplished: and it is certainly all that it has ever collected materials for proving; since no one has ever attempted to exhaust the possible alternative actions in any particular case. Ethical philosophers have in fact confined their attention to a very limited class of actions, which have been selected because they are those which most commonly occur to mankind as possible alternatives. With regard to these they may possibly have shewn that one alternative is better, _i.e._ produces a greater total of value, than others. But it seems desirable to insist, that though they have represented this result as a determination of _duties_, it can never really have been so. For the term duty is certainly so used that, if we are subsequently persuaded that any possible action would have produced more good than the one we adopted, we admit that we failed to do our duty. It will, however, be a useful task if Ethics can determine which among alternatives _likely to occur_ will produce the greatest total value. For, though this alternative cannot be proved to be the best possible, yet it may be better than any course of action which we should otherwise adopt.