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.
