Strange as it may seem, this did not destroy the possibility of what is usually known as scientific knowledge. The so-called laws of nature are dependable at least to some degree even though they are only habits which have been formed in human minds on the basis of what has occurred in the past and the expectation that similar experiences will occur in the future.
Because he denied the possibility of knowing anything that goes beyond the realm of experience, Hume has often been regarded as a thoroughgoing skeptic. However, he did not deny the usefulness of the concepts that are employed in scientific procedure, but he did offer a new explanation of the way in which these concepts are formed. The principles that are involved in scientific procedure are only constructions of the human mind, but they are reliable insofar as they can be used successfully in the ordering of human experiences.
The use of the empirical method in the field of morals enabled Hume to show in a similar manner how it is that ideas concerning right and wrong conduct have come into existence. The conclusions reached in this area of experience were shocking to many of his contemporaries because they had long been accustomed to think of moral obligations as something that had been derived from some supreme authority and imposed on human beings by a power that was external to them. Whether this source of moral obligation was believed to be the will of God or derived from the nature of reason itself made little difference since the rules regulating conduct that were based upon it could be enforced by any political or ecclesiastical body that happened to be in power. This conception of morality was in Hume's opinion not only an unwarranted one but dangerous and at times injurious to the welfare of human beings. By showing that the principles of morality are not derived from an external authority but are drawn from the experiences of people, he believed he could present a far more accurate and satisfactory account of their origin and existence.
