And here there occurs the FOURTH reflection which I purposed to make, in suggesting the reason why modern philosophers have often followed a course in their moral enquiries so different from that of the ancients. In later times, philosophy of all kinds, especially ethics, have been more closely united with theology than ever they were observed to be among the heathens; and as this latter science admits of no terms of composition, but bends every branch of knowledge to its own purpose, without much regard to the phenomena of nature, or to the unbiassed sentiments of the mind, hence reasoning, and even language, have been warped from their natural course, and distinctions have been endeavoured to be established where the difference of the objects was, in a manner, imperceptible. Philosophers, or rather divines under that disguise, treating all morals as on a like footing with civil laws, guarded by the sanctions of reward and punishment, were necessarily led to render this circumstance, of VOLUNTARY or INVOLUNTARY, the foundation of their whole theory. Every one may employ TERMS in what sense he pleases: but this, in the mean time, must be allowed, that SENTIMENTS are every day experienced of blame and praise, which have objects beyond the dominion of the will or choice, and of which it behoves us, if not as moralists, as speculative philosophers at least, to give some satisfactory theory and explication. A blemish, a fault, a vice, a crime; these expressions seem to denote different degrees of censure and disapprobation; which are, however, all of them, at the bottom, pretty nearly all the same kind of species. The explication of one will easily lead us into a just conception of the others; and it is of greater consequence to attend to things than to verbal appellations. That we owe a duty to ourselves is confessed even in the most vulgar system of morals; and it must be of consequence to examine that duty, in order to see whether it bears any affinity to that which we owe to society. It is probable that the approbation attending the observance of both is of a similar nature, and arises from similar principles, whatever appellation we may give to either of these excellencies.