there may often arise disputes
concerning what is natural or unnatural; and one may in general affirm,
that we are not possessed of any very precise standard, by which these
disputes can be decided. Frequent and rare depend upon the number of
examples we have observed; and as this number may gradually encrease
or diminish, it will be impossible to fix any exact boundaries betwixt
them. We may only affirm on this head, that if ever there was any thing,
which coued be called natural in this sense, the sentiments of morality
certainly may; since there never was any nation of the world, nor any
single person in any nation, who was utterly deprived of them, and
who never, in any instance, shewed the least approbation or dislike of
manners. These sentiments are so rooted in our constitution and temper,
that without entirely confounding the human mind by disease or madness,
it is impossible to extirpate and destroy them.

But nature may also be opposed to artifice, as well as to what is rare
and unusual; and in this sense it may be disputed, whether the notions
of virtue be natural or not. We readily forget, that the designs,
and projects, and views of men are principles as necessary in their
operation as heat and cold, moist and dry: But taking them to be free
and entirely our own, it is usual for us to set them in opposition
to the other principles of nature should it, therefore, be demanded,
whether the sense of virtue be natural or artificial, I am of opinion,
that it is impossible for me at present to give any precise answer to
this question. Perhaps it will appear afterwards, that our sense of some
virtues is artificial, and that of others natural. The discussion of
this question will be more proper, when we enter upon an exact detail of
each particular vice and virtue.

[Footnote 14. 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.]

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 unnat