It was the avowed intention of Mr Hobbes, by propagating these notions, to subject the consciences of men immediately to the civil, and not to the ecclesiastical powers, whose turbulence and ambition, he had been taught, by the example of his own times, to regard as the principal source of the disorders of society. His doctrine, upon this account, was peculiarly offensive to theologians, who accordingly did not fail to vent their indignation against him with great asperity and bitterness. It was likewise offensive to all sound moralists, as it supposed that there was no natural distinction between right and wrong, that these were mutable and changeable, and depended upon the mere arbitrary will of the civil magistrate. This account of things, therefore, was attacked from all quarters, and by all sorts of weapons, by sober reason as well as by furious declamation.
In order to confute so odious a doctrine, it was necessary to prove, that antecedent to all law or positive institution, the mind was naturally endowed with a faculty, by which it distinguished in certain actions and affections, the qualities of right, laudable, and virtuous, and in others those of wrong, blamable, and vicious.
Law, it was justly observed by Dr Cudworth, could not be the original source of those distinctions; since upon the supposition of such a law, it must either be right to obey it, and wrong to disobey it, or indifferent whether we obeyed it, or disobeyed it. That law which it was indifferent whether we obeyed or disobeyed, could not, it was evident, be the source of those distinctions; neither could that which it was right to obey and wrong to disobey, since even this still supposed the antecedent notions or ideas of right and wrong, and that obedience to the law was conformable to the idea of right, and disobedience to that of wrong.
Since the mind, therefore, had a notion of those distinctions antecedent to all law, it seemed necessarily to follow, that it derived this notion from reason, which pointed out the difference between right and wrong, in the same manner in which it did that between truth and falsehood: and this conclusion, which, though true in some respects, is rather hasty in others, was more easily received at a time when the abstract science of human nature was but in its infancy, and before the distinct offices and powers of the different faculties of the human mind had been carefully examined and distinguished from one another. When this controversy with Mr Hobbes was carried on with the greatest warmth and keenness, no other faculty had been thought of from which any such ideas could possibly be supposed to arise. It became at this time, therefore, the popular doctrine, that the essence of virtue and vice did not consist in the conformity or disagreement of human actions with the law of a superior, but in their conformity or disagreement with reason, which was thus considered as the original source and principle of approbation and disapprobation.
That virtue consists in conformity to reason, is true in some respects, and this faculty may very justly be considered as, in some sense, the source and principle of approbation and disapprobation, and of all solid judgments concerning right and wrong. It is by reason that we discover those general rules of justice by which we ought to regulate our actions: and it is by the same faculty that we form those more vague and indeterminate ideas of what is prudent, of what is decent, of what is generous or noble, which we carry constantly about with us, and according to which we endeavour, as well as we can, to model the tenor of our conduct. The general maxims of morality are formed, like all other general maxims, from experience and induction. We observe in a great variety of particular cases what pleases or displeases our moral faculties, what these approve or disapprove of, and, by induction from this experience, we establish those general rules. But induction is always regarded as one of the operations of reason. From reason, therefore, we are very properly said to derive all those general maxims and ideas. It is by these, however, that we regulate the greater part of our moral judgments, which would be extremely uncertain and precarious if they depended altogether upon what is liable to so many variations as immediate sentiment and feeling, which the different states of health and humour are capable of altering so essentially. As our most solid judgments, therefore, with regard to right and wrong, are regulated by maxims and ideas derived from an induction of reason, virtue may very properly be said to consist in a conformity to reason, and so far this faculty may be considered as the source and principle of approbation and disapprobation.
But though reason is undoubtedly the source of the general rules of morality, and of all the moral judgments which we form by means of them; it is altogether absurd and unintelligible to suppose that the first perceptions of right and wrong can be derived from reason, even in those particular cases upon the experience of which the general rules are formed. These first perceptions, as well as all other experiments upon which any general rules are founded, cannot be the object of reason, but of immediate sense and feeling. It is by finding in a vast variety of instances that one tenor of conduct constantly pleases in a certain manner, and that another as constantly displeases the mind, that we form the general rules of morality. But reason cannot render any particular object either agreeable or disagreeable to the mind for its own sake. Reason may show that this object is the means of obtaining some other which is naturally either pleasing or displeasing, and in this manner may render it either agreeable or disagreeable for the sake of something else. But nothing can be agreeable or disagreeable for its own sake, which is not rendered such by immediate sense and feeling. If virtue, therefore, in every particular instance, necessarily pleases for its own sake, and if vice as certainly displeases the mind, it cannot be reason, but immediate sense and feeling, which, in this manner, reconciles us to the one, and alienates us from the other.
Pleasure and pain are the great objects of desire and aversion: but these are distinguished not by reason, but by immediate sense and feeling. If virtue, therefore, be desirable for its own sake, and if vice be, in the same manner, the object of aversion, it cannot be reason which originally distinguishes those different qualities, but immediate sense and feeling.
As reason, however, in a certain sense, may justly be considered as the principle of approbation and disapprobation, these sentiments were, through inattention, long regarded as originally flowing from the operations of this faculty. Dr Hutcheson had the merit of being the first who distinguished with any degree of precision in what respect all moral distinctions may be said to arise from reason, and in what respect they are founded upon immediate sense and feeling. In his illustrations upon the moral sense he has explained this so fully, and, in my opinion, so unanswerably, that, if any controversy is still kept up about this subject, I can impute it to nothing, but either to inattention to what that gentleman has written, or to a superstitious attachment to certain forms of expression, a weakness not very uncommon among the learned, especially in subjects so deeply interesting as the present, in which a man of virtue is often loath to abandon, even the propriety of a single phrase which he has been accustomed to.