*28* IX. The motives for failure to prevent injury and so for slighting duty are likely to be various: people either are reluctant to incur enmity or trouble or expense; #a. Preoccupation.# or through indifference, indolence, or incompetence, or through some preoccupation or self-interest they are so absorbed that they suffer those to be neglected whom it is their duty to protect. And so there is reason to fear that what Plato declares of the philosophers may be inadequate, when he says that they are just because they are busied with the pursuit of truth and because they despise and count as naught that which most men eagerly seek and for which they are prone to do battle against each other to the death. For they secure one sort of justice, to be sure, in that they do no positive wrong to anyone, but they fall into the opposite injustice; for hampered by their pursuit of learning they leave to their fate those whom they ought to defend. And so, Plato thinks, they will not even assume their civic duties except under compulsion. But in fact it were better that they should assume them of their own accord; for an action intrinsically right is just only on condition that it is voluntary. #b. Self-interest.# *29* There are some also who, either from zeal in attending to their own business or through some sort of aversion to their fellow-men, claim that they are occupied solely with their own affairs, without seeming to themselves to be doing anyone any injury. But while they steer clear of the one kind of injustice, they fall into the other: they are traitors to social life, for they contribute to it none of their interest, none of their effort, none of their means. #Rules of duty required by Justice.# Now since we have set forth the two kinds of injustice and assigned the motives that lead to each, and since we have previously established the principles by which justice is constituted, we shall be in a position easily to decide what our duty on each occasion is, unless we are extremely self-centred; *30* for indeed it is not an easy matter to be really concerned with other people's affairs; and yet in Terence's play, we know, Chremes "thinks that nothing that concerns man is foreign to him." Nevertheless, when things turn out for our own good or ill, we realize it more fully and feel it more deeply than when the same things happen to others and we see them only, as it were, in the far distance; and for this reason we judge their case differently from our own. It is, therefore, an excellent rule that they give who bid us not to do a thing, when there is a doubt whether it be right or wrong; for righteousness shines with a brilliance of its own, but doubt is a sign that we are thinking of a possible wrong.