Page:Principia Ethica 1922.djvu/196

162 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.

(α) Since, as I have tried to shew, it is impossible to establish that any kind of action will produce a better total result than its alternative in all cases, it follows that in some cases the neglect of an established rule will probably be the best course of action possible. The question then arises: Can the individual ever be justified in assuming that his is one of these exceptional cases? And it seems that this question may be definitely answered in the negative. For, if it is certain that in a large majority of cases the observance of a certain rule is useful, it follows that there is a large probability that it would be wrong to break the rule in any particular case; and the uncertainty of our knowledge both of effects and of their value, in particular cases, is so great, that it seems doubtful whether the individual’s judgment that the effects will probably be good in his case can ever be sent against the general probability that that kind of action is wrong. Added to this general ignorance is the fact that, if the question arises at all, our judgment will generally be biased by the fact that we strongly desire one of the results which we hope to obtain by breaking the rule. It seems, then, that with regard to any rule which is generally useful, we may assert that it ought always to be observed, not on the ground that in every particular case it will be useful, but on the ground that in any particular case the probability of its being so is greater than that of our being likely to decide rightly that we have before us an instance of its disutility. In short, though we may be sure that there are cases where the rule should be broken, we can never know which those cases are,