Chapter III. gives reflections upon the utility of this constitution of our nature. Human beings are dependent upon one another for mutual assistance, and are exposed to mutual injuries. Society might exist without love or beneficence, but not without mutual abstinence from injury. Beneficence is the ornament that embellishes the building; Justice the main pillar that supports it. It is for the observance of Justice that we need that consciousness of ill-desert, and those terrors of mental punishment, growing out of our sympathy with the disapprobation of our fellows. Justice is necessary to the existence of society, and we often defend its dictates on that ground; but, without looking to such a remote and comprehensive end, we are plunged into remorse for its violation by the shorter process of referring to the censure of a supposed spectator [in other words, to the sanction of public opinion]. _Section III.--Of the influence of Fortune upon the sentiments of mankind, with regard to the Merit and the Demerit of actions_. Every voluntary action consists of three parts:--(1) the Intention or motive, (2) the Mechanism, as when we lift the hand, and give a blow, and (3) the Consequences. It is, in principle, admitted by all, that only the first, the Intention, can be the subject of blame. The Mechanism is in itself indifferent. So the Consequences cannot be properly imputed to the agent, unless intended by him. On this last point, however, mankind do not always adhere to their general maxim; when they come to particular cases, they are influenced, in their estimate of merit and demerit, by the actual consequences of the action. Chapter I. considers the causes of this influence of Fortune. Gratitude requires, in the first instance, that some pleasure should have been conferred; Resentment pre-supposes pain. These passions require farther that the object of them should itself be susceptible of pleasure and pain; they should be human beings or animals. Thirdly, It is requisite that they should have produced the effects from a design to do so. Now, the absence of the pleasurable consequences intended by a beneficent agent leaves out one of the exciting causes of gratitude, although including another; the absence of the painful consequences of a maleficent act leaves out one of the exciting causes of resentment; hence less gratitude seems due in the one, and less resentment in the other. Chapter II. treats of the extent of this influence of Fortune. The effects of it are, first, to diminish, in our eyes, the merit of laudable, and the demerit of blameable, actions, when they fail of their intended effects; and, secondly, to increase the feelings of merit and of demerit beyond what is due to the motives, when the actions chance to be followed by extraordinary pleasure or pain. Success enhances our estimate of all great enterprises; failure takes off the edge of our resentment of great crimes.