Mean while, it may not be amiss to observe, from these definitions of _natural_ and _unnatural_, that nothing can be more unphilosophical than those systems which assert, that virtue is the same with what is natural, and vice with what is unnatural. For, in the first sense of the word, nature, as opposed to miracles, both vice and virtue are equally natural; and, in the second sense, as opposed to what is unusual, perhaps virtue will be found to be the most unnatural. At least it must be owned, that heroic virtue, being as unusual, is as little natural as the most brutal barbarity. As to the third sense of the word, 'tis certain that both vice and virtue are equally artificial and out of nature. For, however it may be disputed, whether the notion of a merit or demerit in certain actions, be natural or artificial, 'tis evident that the actions themselves are artificial, and are performed with a certain design and intention; otherwise they could never be ranked under any of these denominations. 'Tis impossible, therefore, that the character of natural and unnatural can ever, in any sense, mark the boundaries of vice and virtue. Thus we are still brought back to our first position, that virtue is distinguished by the pleasure, and vice by the pain, that any action, sentiment, or character, gives us by the mere view and contemplation. This decision is very commodious; because it reduces us to, this simple question, _Why any action or sentiment, upon the general view or survey, gives a certain satisfaction or uneasiness_, in order to show the origin of its moral rectitude or depravity, without looking for any incomprehensible relations and qualities, which never did exist in nature, nor even in our imagination, by any clear and distinct conception? I flatter myself I have executed a great part of my present design by a state of the question, which appears to me so free from ambiguity and obscurity. [4] In the following discourse, _natural_ is also opposed sometimes to _civil_, sometimes to _moral_. The opposition will always discover the sense in which it is taken. PART II. OF JUSTICE AND INJUSTICE. SECTION I. JUSTICE, WHETHER A NATURAL OR ARTIFICIAL VIRTUE? I have already hinted, that our sense of every kind of virtue is not natural; but that there are some virtues that produce pleasure and approbation by means of an artifice or contrivance, which arises from the circumstances and necessity of mankind. Of this kind I assert _justice_ to be; and shall endeavour to defend this opinion by a short, and, I hope, convincing argument, before I examine the nature of the artifice, from which the sense of that virtue is derived.