Having explained the universal sense of approbation for that which is virtuous and meritorious, it remains for Hume to show how the sense of obligation is related to that which is pleasant and agreeable. One of the major issues in all moral philosophy is that of the relationship between what one likes to do and what it is that he ought to do. It is not at all uncommon to find those who not only make a sharp distinction between these two but often find that they are directly opposed to each other. This is especially true of those who have advocated a rationalistic basis for ethics. Immanuel Kant in modern times, and the Stoic philosophers of the ancient world have maintained that the demands of reason do not normally coincide with human desires. From their point of view, the moral person is one who follows the dictates of his rational nature and keeps his feelings and desires under subjection and control.
Hume does not agree with this position, and he believes he has good reasons for rejecting it. The main reason is that the intellect is by itself powerless to move the will and thus to produce any concrete actions. Its function is confined to that of supplying information concerning facts, and this alone is not sufficient to cause a person to act. Any system of morals that is derived from the nature of reason or any of its demands will not be carried out in actual practice unless there is a desire to act in conformity with it. There can be no merit in the establishment of a code of ethics that is so rigorous and austere that no one is able to follow it.
What Hume proposes in contrast to an ethics of reason is one that is based on the natural feelings and desires of human beings. When the good is identified with that which is pleasant and agreeable to those humane elements in human nature which respond to whatever is beneficial to the members of society, it will be more likely to be followed. An ethics based on feelings and desires will not only have the advantage of being followed, but it will include all of those virtues which are beneficial to human beings, and at the same time it will exclude all of those practices which are detrimental to human welfare.
At the beginning of this section, Hume explains in part one of the main purposes which led to the writing of the Enquiry. He wanted to counteract some of the unfortunate consequences which had been derived from the more popular conceptions of morality that were current in his day.
One should bear in mind that at this time, the field of morality was for most people closely related to the area of religion. In both of these areas, it was customary to refer to divine revelation in support of what was believed to be true. This concept of revelation was usually interpreted to mean that the ideas associated with the will of God were communicated directly and infallibly to the minds of human beings. From this it would follow that certain individuals would know with absolute certainty the content of the mind of God with reference to human conduct. This would enable them to prescribe with definiteness and precision the exact rules and regulations which ought to be followed.
Regardless of any merit which might be found in this practice of identifying one's beliefs about morality with the will of God, this kind of procedure was bound to have some very unfortunate consequences. For one thing, it tended to produce an attitude of arrogance on the part of those who claimed to know with certainty the distinctions between good and bad conduct. Furthermore, it led to intolerance and often to persecution of those who did not agree or who failed to conform to the requirements set forth. Again it lent support to the idea that certain types of conduct were always either good or bad, and this quite apart from the circumstances under which they were performed or the effects which they might have on the welfare of the people that were involved. It was in this way, according to Hume, that such practices as celibacy, fasting, penance, self-denial, and in his words "the whole train of monkish virtues" had come to be recognized as righteous behavior.
Hume was convinced that many of these practices were not only ill-founded but decidedly detrimental to human welfare. He believed that something ought to be done to correct this situation. His method for doing this was to show that the principles of morality are in reality based on the facts of human experience and not on some authoritarian basis which claims to be identical with the will of God.
It should be noted in this connection that Hume does not deny that there is something which may appropriately be called the will of God, but he does challenge the notion that any human being knows exactly what it is. Hence, it is a mistake to base the principles of morality on what one thinks the eternal and unchanging will of God may be. On the other hand, a system of morals that is derived from the facts of human experience can be adapted to the changing circumstances which arise from time to time. It can always be directed toward the welfare of human beings, and while the application of its principles will lack the rigidity of a formalistic system, it will provide for a greater amount of freedom for the people who are involved.
In criticism of Hume's doctrine, it should be pointed out that, while a system of morals that is based solely on human experience does not have the same defects which appear in an authoritarian system, there are other ones which make its validity questionable. For example, one may ask whether there is anything in human experience that indicates any difference between what is good and what is bad or tells one what it is that he ought to do. Experience can tell us what consequences have followed certain actions, but this does not tell us whether the consequences have been good or bad. It may be that we like some of the consequences or that we dislike certain things that have happened, but this is not equivalent to saying which ones are good or which ones are bad.
This much Hume appears to have recognized, for in his discussion of the function of reason, he makes it very clear that reason can reveal only matters of fact, and it is quite impossible to derive what ought to be from what is. However, there is no other way on an empirical basis for one to distinguish between activities that are good and the ones that are bad. Those who do attempt to make distinctions of this kind are forced by the logic of the situation to identify what is good with that which is approved because one finds it both pleasant and agreeable. This would imply that the word "good" in the moral sense of the term means nothing other than that which is liked or approved.
This interpretation of goodness, while consistent with the empirical method which Hume followed, leaves unanswered some very difficult questions. How, for example, can one refer to any activity as bad so long as the person who is doing it finds it both pleasant and agreeable? Nevertheless, it is true that there are many instances in everyday life where activities that are generally regarded as bad are found to be pleasant and agreeable on the part of those who perform them.
Hume attempts to avoid this difficulty by identifying actions as good only when they are approved by a majority of the members of a given society. This does appear to help the situation, but it does not answer in a satisfactory way the objections which may be raised to this method of dealing with the problem. On what basis can we say that in moral matters the opinion of the majority is necessarily the right one? Past experiences indicate quite clearly that majorities have often been in the wrong. At least they have done things which at a later date have come to be regarded as wrong.
The fact of the matter is that any valid distinction between what is right and what is wrong implies some notion of a fixed standard according to which the judgment is made. Although the idea of a fixed standard of goodness has been rejected by Hume throughout the entire course of his arguments, he is forced to admit one into his system of moral philosophy in order to make it complete. He does this by admitting that human nature is so constituted that there is present in it a sense of humanity which always approves of that which is useful for the promotion of human welfare and which necessarily disapproves of that which is contrary to it. This sense of humanity, he tells us, is the same in all persons, although the extent to which it is expressed may vary with different individuals. This, accordingly, is the standard which in the last analysis determines whether an act is right or wrong.
The place which Hume gives to the feelings in determining the moral quality of an act follows from his conviction that the intellect by itself is powerless to cause one to act. In this he was correct, and the point which he makes constitutes a valid criticism of Kant's rationalistic ethics. On the other hand, it must be recognized that it is just as impossible to build a system of ethics on feelings alone as it is to build one on the intellect alone. One's feelings are essential for moral conduct, but if these feelings are to have any significance in the determination of what is right, they must be guided by intelligence. The only way in which this can be done is for the intellect to apply the standard of goodness to the particular action in question.