ABSTRACT
There is therefore much truth in the description of the right act as a fortunate act. If we cannot be certain that it is right, it is our good fortune if the act we do is the right act. This consideration does not, however, make the doing of our duty a mere matter of chance. There is a parallel here between the doing of duty and the doing of what will be to our personal advantage. We never know what act will in the long run be to our advantage. Yet it is certain that we are more likely in general to secure our advantage if we estimate to the best of our ability the probable tendencies of our actions in this
latter. That an act, qua fulfilling a promise, or qua effecting a just distribution of good, or qua returning services rendered, or qua promoting the good of others, or qua promoting the virtue or insight of the agent, is prima facie right, is self-evident; not in the sense that it is evident from the beginning of our lives, or as soon as we attend to the proposition for the first time, but in the sense that when we have reached sufficient mental maturity and have given sufficient attention to the proposition it is evident without any need of proof, or of evidence beyond itself. It is self-evident just as a mathematical axiom, or the validity of a form of inference, is evident. The moral order expressed in these propositions is just as much part of the fundamental nature of the universe (and, we may add, of any possible universe in which there were moral agents at all) as is the spatial or numerical structure expressed in the axioms of geometry or arithmetic. In our confidence that these propositions are true there is involved the same trust in our reason that is involved in our confidence in mathematics and we should have no justification for trusting it in the latter sphere and distrusting it in the former. In both cases we are dealing with propositions that cannot be proved, but that just as certainly need no proof. . . .
