Ethics of end and right conduct
Though Moore (1959 ) criticizes utilitarianism about the nature of the good, he recommends right conduct very similar to that recommended by utilitarianism. Among alternative possible actions, it is necessary to determine the one that will generally produce the expected greatest good - identified with the ideal. This is the 'ideal utilitarianism'. The pursuit of the greatest good is favoured by the general observance of rules or actions of general utility,8 such as respect for liberty and private property, industriousness, and temperance. When rules or actions are proved to be of general utility, an agent 'should always perform them; but in other cases ... he should rather judge of the probable results in his particular case, guided by a correct conception of what things are intrinsically good or bad' (1959 , p. 181). According to Moore, judgements based on frequencies should be the only cases of probability that have logical relevance.
Nevertheless, Moore (1959 , pp. 149-54) specifies that rational decision makers meet difficulties in choosing the best action. The problem is about practical ethics, intended as the investigation of the probable reasons of action or the pursuit of the moral good according to a reasonable or probable expectation of obtaining it, given the agent's knowledge. He claims that
it is obvious that our causal knowledge alone is far too incomplete for us to assure ourselves of this result. Accordingly it follows that . we can never be sure that any action will produce the greatest value possible. ... The utmost, then, that Practical Ethics can hope to discover is which, among a few alternatives possible under certain circumstances, will, on the whole, produce the best result. ... But it is plain that even this is a task of immense difficulty. . The first difficulty in the way of establishing a probability that one course of action will give a better total result than another, lies in the fact that we have to take account of the effects of both throughout an infinite future. ... It is quite certain that our causal knowledge is utterly insufficient to tell us what different effects will probably result from two different actions, except within a comparatively short space of time.