If man can predict, almost with certainty, those appearances of which he understands the laws; if, even when the laws are unknown to him, experience or the past enables him to foresee, with considerable probability, future appearances; why should we suppose it a chimerical undertaking to delineate, with some degree of truth, the picture of the future destiny of mankind from the results of its history? The only foundation of faith in the natural sciences is the principle, that the general laws, known or unknown, which regulate the phenomena of the universe, are regular and constant; and why should this principle, applicable to the other operations of nature, be less true when applied to the developement of the intellectual and moral faculties of man? In short, as opinions formed from experience, relative to the same class of objects, are the only rule by which men of soundest understanding are governed in their conduct, why should the philosopher be proscribed from supporting his conjectures upon a similar basis, provided he attribute to them no greater certainty than the number, the consistency, and the accuracy of actual observations shall authorise?