When, however, we come to investigate this question we are met with a difficulty in the arrangement of the subject, which, like most difficulties of classification, deserves attentive consideration, as it depends upon important characteristics of the matter that has to be arranged. In a narrower sense of the term, Benevolence is not unfrequently distinguished from--and even contrasted with--Justice; we may of course exercise both towards the same persons, but we commonly assume that the special function of Benevolence begins where Justice ends; and it is rather with this special function that we are concerned in considering claims to affection, and to kind services normally prompted by affection. At the same time, if we consider these services as strictly due to persons in certain relations, the moral notion under which these duties are presented to us is not easily distinguishable from that of Justice; while yet these duties can hardly be withdrawn from the sphere of Benevolence in the narrowest sense. It is sometimes given as a distinction between Justice and Benevolence, that the services which Justice prescribes can be claimed as a right by their recipient, while Benevolence is essentially unconstrained: but we certainly think (_e.g._) that parents have a right to filial affection and to the services that naturally spring from it. It is further said that the duties of Affection are essentially indefinite, while those we classify under the head of Justice are precisely defined: and no doubt this is partly true. We not only find it hard to say exactly how much a son owes his parents, but we are even reluctant[192] to investigate this: we do not think that he ought to ask for a precise measure of his duty, in order that he may do just so much and no more; while a great part of Justice consists in the observance of stated agreements and precise rules. At the same time it is difficult to maintain this distinction as a ground of classification; for the duties of Affection are admittedly liable to come into competition with each other, and with other duties; and when this apparent conflict of duties occurs, we manifestly need as precise a definition as possible of the conflicting obligations, in order to make a reasonable choice among the alternatives of conduct presented to us. Accordingly in the following chapter (§ 2) I shall show how this competition of claims renders our common notion of Justice applicable to these no less than to other duties: meanwhile, it seems proper to treat here separately of all duties that arise out of relations where affection normally exists, and where it ought to be cultivated, and where its absence is deplored if not blamed. For all are agreed that there are such duties, the non-performance of which is a ground for censure, beyond the obligations imposed by law, or arising out of specific contract, which will come under a different head.