One or other of these objections seems generally to apply to proposed changes in social custom, advocated as being better rules to follow than those now actually followed; and, for this reason, it seems doubtful whether Ethics can establish the utility of any rules other than those generally practised. But its inability to do so is fortunately of little practical moment. The question whether the general observance of a rule not generally observed, would or would not be desirable, cannot much affect the question how any individual ought to act; since, on the one hand, there is a large probability that he will not, by any means, be able to bring about its general observance, and, on the other hand, the fact that its general observance would be useful could, in any case, give him no reason to conclude that he himself ought to observe it, in the absence of such general observance. With regard, then, to the actions commonly classed in Ethics, as duties, crimes, or sins, the following points seem deserving of notice. (1) By so classing them we mean that they are actions which it is possible for an individual to perform or avoid, if he only _wills_ to do so; and that they are actions which _everybody_ ought to perform or avoid, when occasion arises. (2) We can certainly not prove of any such action that it ought to be done or avoided under _all_ circumstances; we can only prove that its performance or avoidance will _generally_ produce better results than the alternative. (3) If further we ask of what actions as much as this can be proved, it seems only possible to prove it with regard to those which are actually generally practised among us. And of these some only are such that their general performance would be useful in any state of society that seems possible; of others the utility depends upon conditions which exist now, but which seem to be more or less alterable. =99.= (_d_) So much, then, for moral rules or laws, in the ordinary sense--rules which assert that it is generally useful, under more or less common circumstances, for _everybody_ to perform or omit some definite kind of action. It remains to say something with regard to the principles by which _the individual_ should decide what he ought to do, (α) with regard to those actions as to which some general rule is certainly true, and (β) with regard to those where such a certain rule is wanting.