"Philosophy is even more diverse and changeable than other sciences.[1] At first sight the contrary of this would seem to be true; for whereas the 'belles lettres' are concerned with the study of the beautiful, which is chiefly a matter of custom and opinion, sciences seek the truth, which is fixed and unchangeable. But this truth is hid from mortals, though, as centuries go by, some little of it is revealed. Consequently, on the one hand, in their endeavours to discover it, and their conjectures as to its nature, men are led to embrace this or that resemblance of truth; thereupon opinions and sects multiply. And, on the other hand, it is due to the ever-increasing number of fresh discoveries, and new aspects of truth obtained daily, that even these divisions become subdivided; and opinions which at one time were regarded almost as certainties change shape and substance momentarily. It is owing to the changeability of sciences and philosophy that they are so unproductive of glory, either at the hands of contemporaries or posterity. For when new discoveries, or new ideas and conjectures, greatly alter the condition of this or that science from its present state, how will the writings and thoughts of men now celebrated in these sciences be regarded? Who, for instance, now reads Galileo's works? Yet in his time they were most wonderful; nor could better and nobler books, full of greater discoveries and grander conceptions, be then written on such subjects. But now every tyro in physics or mathematics surpasses Galileo in his knowledge. Again, how many people in the present day read the writings of Francis Bacon? Who troubles himself about Malebranche? And how much time will soon be bestowed on the works of Locke, if the science almost founded by him progresses in future as rapidly as it gives promise of doing? "Truly the very intellectual force, industry, and labour, which philosophers and scientists expend in the pursuit of their glory, are in time the cause of its extinction or obscurÈment. For by their own great exertions they open out a path for the still further advancement of the science, which in time progresses so rapidly that their writings and names fall gradually into oblivion. And it is certainly difficult for most men to esteem others for a knowledge greatly inferior to their own. Who can doubt that the twentieth century will discover error in what the wisest of us regard as unquestionable truths, and will surpass us greatly in their knowledge of the truth?"