among those _arcana_ of nature that are not to be revealed to human understanding. But, although these phænomena in nature are not to be accounted for, and therefore admit of no principle of law inferible from them; yet their very incomprehensibleness, when compared with other circumstances more known and better understood, may serve to this end, as so many lesser weights in the scales of greater probability. Now, my Lord, it is an opinion _universally_ received, that human nature is _universally_ the same: but I should apprehend that this was a proportion rather taken for granted, than admitted to be proved: for although the proper study of mankind is man, and therefore the universality of such an opinion is _prima facie_ evidence of its truth; yet, it is to be observed, that, of all other studies, the science of man has been least of all cultivated and improved. Man only, who examines all Nature else, stands unexamined by himself. If we look into the vegetable and mineral kingdoms of this world, we shall perceive a scrutiny made in them the most nice, accurate, and comprehensive, we shall find these grand divisions of nature arranged in classes, orders, kinds, and sorts: we shall contemplate systems morally perfect. If we take a view of the animal kingdom below ourselves, we shall be witnesses there also of the same order, regularity, and perfection. Why then is human nature exempt from this disquisition and arrangement? Are men afraid to turn their eyes upon themselves, lest they behold themselves in the mirror of truth? Or is it pride, or vanity, that causes this neglect? Yes, men would be angels, angels would be gods, says Mr. Pope[12]; and yet man, as Dr. Lister observes[13], is as very a quadruped as any animal on earth; and whose actions are most of them resolvable into instinct, notwithstanding the principles which custom and education have superinduced. Of other animals then, it is well known, there are many _kinds_, each kind having its proper _species_ subordinate thereto: but man is one kind of animal, and yet, without distinction of species, _universally the same_. Does not this seem to break in upon and unlink that great chain of Heaven, which in due gradation joins and unites the whole with all its parts? May it not be more perfective of the system to say, that human nature is a _class_, comprehending an _order_ of beings, of which man is the _genus_, divided into distinct and separate _species_ of men? All other species of the animal kingdom have their marks of distinction: why should man be universally indiscriminate one to the other?