That such a law exists can hardly be questioned. Its operation is apparent, not only in the partial experience of our own country, but in that of all others where the natural social tendencies have had unimpeded sway. No one has ever denied its existence among the white races; for there it has operated invariably to bring certain emancipation, whenever any nation has reached the proper position in the scale of progress. The rule is universal; history presents no exception. But it has been supposed that slavery of the African to the white man is not subject to this great historical law, on account of the difference of race, whether that difference be fundamental and ineradicable, or whether it be only the consequence of material conditions operating through successive centuries. Neither reason nor experience, however, can be invoked to sustain this supposed exception to the general law. Except in Spanish America, African slavery has disappeared from the dependencies of European powers; and even there, every one knows, the conditions of slavery are far more favorable to emancipation than in the United States. Yet here, a majority of the original thirteen colonies have wholly discarded slavery, and given themselves up to the dominion of free white men; while others among those known as border States, notwithstanding their apparent immobility, have long been unconsciously preparing to follow in the same path of safety. Even without the rebellion, it is demonstrable, we believe, that the border States could not long have resisted the necessity for gradual, but complete emancipation. The civil war makes it more speedy, not more certain.
In order to establish the principle that slavery, in any part of the United States, is destined to be an exception to that general law which decrees universal emancipation as a certain result, it would be necessary to show the negro to be incapable of improvement; for if he be destined to progressive existence at all, it follows that, sooner or later, he will reach a condition in which he no longer can or ought to be held in subjection or subordination of any kind; and this, too, without the supposition of any moral change or improvement on the part of the slave owner. Indeed, the most usual and plausible, if not also the most truly substantial of all excuses or justifications for enslaving the African, in any form, has, from the beginning, been predicated on the fact that his subordination to the superior intelligence of the white man is calculated to improve him physically, morally, and intellectually. The capacity of improvement thus admitted, the logical result must be eventual liberation. This result is bound up in the very nature of things, and must inevitably be developed at some time or other, as proved by all history, as well as by any rational analysis of human character and intellect. But, only one half the argument has been employed to bring the mind to this irresistible conclusion. We have omitted all examination of the subject in that other aspect which has reference to industrial, economical, and moral considerations affecting the vital interests of the superior race. We need not say how much the discussion of these would serve to strengthen the argument and confirm the conclusion already stated.