Among all the subjects of human cognizance, the least understood, and therefore the most difficult of anticipation, are those which concern the acts of men, as individuals or in society. Presumptuous, indeed, would be that man who should undertake to foretell the exact results of pending political or military operations, complicated as they must be by innumerable unknown and undiscoverable contingencies, which lie hidden in the circumstances of the actual situation. The difficulty of this investigation does not arise, however, from the absence of fixed laws controlling such events, but solely from our ignorance of those laws, and the extreme complexity of the conditions in which they act. The issue of existing causes is as certain as this moment, as it will be after it shall have become unalterable in history. No accident can disturb or thwart it; for, in truth, there can be no such thing as accident, except in our imaginations, and by reason of our incapacity to trace the continuous thread of inevitable sequence, or causation, which connects together all events whatever, in their inception, through their continuance, and to their end. All enlightened thinkers of the present age have recognized this great truth; and yet none have been able to apply to social and political affairs the sole admitted test of genuine philosophy, the prediction of future results from known antecedents. Indeed, the wisest and most competent of political observers have always been the most cautious in their indulgence of the prophetic spirit, and the most ready to acknowledge their ignorance of what the future will bring forth in the great field of political and social affairs. Gasparin, in his late admirable book, 'America before Europe' (according to his American translator), has this very modest passage on this subject: 'Not feeling any vocation for the character of prophet, I shall take care not to recount here, in advance, events that are about to happen. I marvel at people who are so sure of their facts. The future has not the least obscurity for them; it has much for me. I confine myself to protesting against the positive assertions which have contributed but too greatly to mislead the opinion of Europe. My humbles theory is this: the defeat of the South is _probable_; the return of the conquered South to the Union is _possible_.'