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.
