This new power of perception he called a moral sense, and supposed it to be somewhat analogous to the external senses. As the bodies around us, by affecting these in a certain manner, appear to possess the different qualities of sound, taste, odour, colour; so the various affections of the human mind, by touching this particular faculty in a certain manner, appear to possess the different qualities of amiable and odious, of virtuous and vicious, of right and wrong.

The various senses or powers of perception,[[25]] from which the human mind derives all its simple ideas, were, according to this system, of two different kinds, of which the one were called the direct or antecedent, the other, the reflex or consequent senses. The direct senses were those faculties from which the mind derived the perception of such species of things as did not presuppose the antecedent perception of any other. Thus sounds and colours were objects of the direct senses. To hear a sound or to see a colour does not presuppose the antecedent perception of any other quality or object. The reflex or consequent senses, on the other hand, were those faculties from which the mind derived the perception of such species of things as presupposed the antecedent perception of some other. Thus harmony and beauty were objects of the reflex senses. In order to perceive the harmony of a sound, or the beauty of a colour, we must first perceive the sound or the colour. The moral sense was considered as a faculty of this kind. That faculty, which Mr. Locke calls reflection, and from which he derived the simple ideas of the different passions and emotions of the human mind, was, according to Dr. Hutcheson, a direct internal sense. That faculty again by which we perceived the beauty or deformity, the virtue or vice of those different passions and emotions, was a reflex, internal sense.

[25]. Treatise of the passions.

Dr. Hutcheson endeavoured still further to support this doctrine, by shewing that it was agreeable to the analogy of nature, and that the mind was endowed with a variety of other reflex senses exactly similar to the moral sense; such as a sense of beauty and deformity in external objects; a public sense, by which we sympathize with the happiness or misery of our fellow-creatures; a sense of shame and honour, and a sense of ridicule.

But notwithstanding all the pains which this ingenious philosopher has taken to prove that the principle of approbation is founded in a peculiar power of perception, somewhat analogous to the external senses, there are some consequences, which he acknowledges to follow from this doctrine, that will, perhaps, be regarded by many as a sufficient confutation of it. The qualities, he allows,[[26]] which belong to the objects of any sense, cannot, without the greatest absurdity, be ascribed to the sense itself. Who ever thought of calling the sense of seeing black or white, the sense of hearing loud or low, or the sense of tasting sweet or bitter? And, according to him, it is equally absurd to call our moral faculties virtuous or vicious, morally good or evil. These qualities belong to the objects of those faculties, not to the faculties themselves. If any man, therefore, was so absurdly constituted as to approve of cruelty and injustice as the highest virtues, and to disapprove of equity and humanity as the most pitiful vices, such a constitution of mind might indeed be regarded as inconvenient both to the individual and to the society, and likewise as strange, surprising, and unnatural in itself; but it could not, without the greatest absurdity, be denominated vicious or morally evil.

[26]. Illustrations upon the Moral Sense. Sect. 1. p. 237, et seq. Third Edition.

Yet surely if we saw any man shouting with admiration and applause at a barbarous and unmerited execution, which some insolent tyrant had ordered, we should not think we were guilty of any great absurdity in denominating this behaviour vicious and morally evil in the highest degree, though it expressed nothing but depraved moral faculties, or an absurd approbation of this horrid action, as of what was noble, magnanimous, and great. Our heart, I imagine, at the sight of such a spectator, would forget for a while its sympathy with the sufferer, and feel nothing but horror and detestation, at the thought of so execrable a wretch. We should abominate him even more than the tyrant who might be goaded on by the strong passions of jealousy, fear, and resentment, and upon that account be more excusable. But the sentiments of the spectator would appear altogether without cause or motive, and therefore most perfectly and completely detestable. There is no perversion of sentiment or affection which our heart would be more averse to enter into, or which it would reject with greater hatred and indignation than one of this kind; and so far from regarding such a constitution of mind as being merely something strange or inconvenient, and not in any respect vicious or morally evil, we should rather consider it as the very last and most dreadful stage of moral depravity.

Correct moral sentiments, on the contrary, naturally appear in some degree laudable and morally good. The man, whose censure and applause are upon all occasions suited with the greatest accuracy to the value or unworthiness of the object, seems to deserve a degree even of moral approbation. We admire the delicate precision of his moral sentiments: they lead our own judgments, and, upon account of their uncommon and surprising justness, they even excite our wonder and applause. We cannot indeed be always sure that the conduct of such a person would be in any respect correspondent to the precision and accuracy of his judgments concerning the conduct of others. Virtue requires habit and resolution of mind, as well as delicacy of sentiment; and unfortunately the former qualities are sometimes wanting, where the latter is in the greatest perfection. This disposition of mind, however, though it may sometimes be attended with imperfections, is incompatible with any thing that is grossly criminal, and is the happiest foundation upon which the superstructure of perfect virtue can be built. There are many men who mean very well, and seriously purpose to do what they think their duty, who notwithstanding are disagreeable on account of the coarseness of their moral sentiments.

It may be said, perhaps, that though the principle of approbation is not founded upon any power of perception that is in any respect analogous to the external senses, it may still be founded upon a peculiar sentiment which answers this one particular purpose and no other. Approbation and disapprobation, it may be pretended, are certain feelings or emotions which arise in the mind upon the view of different characters and actions; and as resentment might be called a sense of injuries, or gratitude a sense of benefits, so these may very properly receive the name of a sense of right and wrong, or of a moral sense.

But this account of things, though it may not be liable to the same objections with the foregoing, is exposed to others which are equally unanswerable.