Those who deny that there is any difference between right and wrong, along with those whose opinions about morals are so fixed that they will not change no matter what evidence can be presented against them, are not likely to be influenced by argument. It is the part of wisdom to leave them alone and trust that in due time they will come to their senses and accept the view which to the average person seems so obvious that he is never inclined to doubt it. But acceptance of the idea that a valid distinction can be made between right and wrong does not settle all the questions that arise when one thinks seriously about the origin and meaning of moral beliefs.
One of the major issues that has long been associated with moral philosophy has to do with the question of whether the basis for moral distinctions is to be found in the reason or in the sentiments and feelings experienced by human beings. The issue is as old as the history of philosophy and persists even to the present time. Among the ancient Greeks, there were those who regarded morality as essentially a matter of the feelings and attitudes which one displayed toward his fellow humans. At the same time, there were others who believed that goodness was primarily a matter of the intelligence.
These opposing points of view can be found in almost every period of human history. There have been extremists on both sides of the question. On one side, they have shown a strong tendency to make morality purely a matter of the feelings, while their opponents have been equally convinced that it is purely a matter of the intellect. It requires only a small amount of reflection to see that both reason and the feelings are necessary for the formation of moral judgments, but there are differences of opinion concerning the respective place that should be assigned to each. It is for the purpose of throwing light on this important question that this study has been undertaken.
It can be seen at once that the question of reason or sentiment as the basis for moral judgments is something more than an academic issue. The practical consequences which follow from these opposite points of view are of the greatest significance for estimating the values of human life. If moral judgments are derived from reason, they can be true or false. If they are based solely on the feelings, there can be no dispute concerning them. Truth is disputable but taste is not. Again, if moral judgments are true in the same sense that propositions in mathematics are true, they are not subject to change. The principles of morality would in that case be as eternal as the laws of mathematics. But if moral judgments are derived from the feelings, they do not remain constant. They will be as variable as the moods and sentiments of the individuals who make them.
The issue is a crucial one so far as the status of moral principles is concerned. Arguments have been stated in abundance in support of each of these opposing positions. Hume's own position is very definitely on the side of those who place the greater emphasis on feelings rather than reason as the basis for moral beliefs.
Several of Hume's contemporaries, as well as his predecessors, had given support to the rationalistic conception of ethics, and he was anxious to correct the errors which he saw in the views they had presented. His method for doing this was quite in harmony with the spirit of empiricism, which was being emphasized in the scientific inquiries of his day.
In contrast with the rationalists, who had derived their principles of morality by making deductions from metaphysical assumptions, Hume believed it was necessary to study the facts of human experience and to draw only those conclusions which are warranted by the facts. He regarded the attempt to base morality on one's conception of the nature of the universe a misguided one. Any knowledge that can be gained with reference to morals must come from a different source. He therefore proposes to begin the inquiry by examining the way in which moral ideas have been formed. Because the principles of benevolence and justice have been widely recognized as virtuous by people of all races and cultures, he begins with an investigation of the meanings that have been associated with these terms.
The first section of the Enquiry is a general introduction to the book as a whole. Hume begins with a clear statement of the major issue involved in ethical philosophy from the times of Plato and Aristotle to the day in which he lived. It might be added that the same problems are still the central ones in ethical discussions at the present time.
The main point at issue has to do with the nature of the principles of morality. Are they static or dynamic? Do they remain the same for all people and for all time, or do they change along with the customs and environmental conditions of the people who are affected by them? Are they derived from some permanent and supreme source which never changes, or are they derived from the changing and transitory facts of human experience? Are moral principles based on reason or on feelings? Is the basis for morality to be found in some metaphysical conception of the universe, or is it derived solely from the particular facts of experience? These are the questions which moralists of all ages have tried to answer, and anyone who is familiar with contemporary literature on morals knows that the present time is no exception.
It is significant that the title of Hume's book is called an Enquiry, for he was not under the illusion that he was able to pronounce the final answer to all of these questions. He abhorred dogmatism in any of its forms and did not want it to even appear that he was guilty of it in the writing of this book. Nevertheless, he did have some very definite convictions about the nature of morality, and he was confident that he could expose at least some of the errors that had been current in the ethical literature of his day and thus point the way toward a more adequate understanding of one of the most important areas of human existence. He knew very well that what he had to say would not be convincing to some people, for there are many persons whose minds have become so fixed on the acceptance of certain ideas that no amount or quality of argument would ever cause them to change. On the other hand, there are many persons who are intellectually honest and who will not hesitate to reexamine their beliefs in the light of new evidence, and it was to persons of this type that the message of his book was directed.
One of the main sources of dogmatism in the field of morals has been the conviction that one's own beliefs are true and those of persons who do not agree are therefore false. It was the assumption on which convictions of this type are based that Hume called in question.
Is it possible to have beliefs about what is morally right or wrong that are really true or false? The answer to this question would in his judgment depend on whether moral beliefs are like those based on matters of fact or the ones that are merely matters of taste. What one believes about matters of fact can be true or false, but this is not the case with reference to matters of taste. Apart from our own experiences, the only beliefs about which we can have complete or absolute certainty are the ones which are derived from reason alone. Propositions in the fields of mathematics and logic are illustrative of this type of certainty. Beliefs that are based on the facts of experience may have a high or low degree of probability, but those that are based on personal feelings and matters of individual preference cannot be called into question. It is for this reason that they cannot be said to be either true or false.
To understand the nature of moral principles and beliefs, it is necessary to examine some typical ones for the purpose of determining their origin and the basis for their existence. Because acts of justice and benevolence are among those which are most widely approved, he begins with an analysis of them.