rise around you the problems which form the object of the moral disciplines. Such is the intimate complexity of the two orders of knowledge that a persevering reflection discovers them to be everywhere mingled, and it is with difficulty that they are disentangled. All knowledge is an aggregate (_ensemble_) of judgments; but the judgments which constitute physical knowledge and those that constitute moral science are not of the same nature. The first are judgments of _existence_, bearing solely on the causality, the succession, the distribution of phenomena, _i.e._ on the relations of objects to each other, apart from the subject. The basis on which they rest is sensation, and, as sensation has for necessary forms time and space, time and space will also be the forms and limits of these judgments. Forming homogeneous quantities, time and space give the notion of figure and of number, so that mathematics is the foundation and the necessary framework of all the physical sciences. They rise above this abstract science of the forms of sensibility in the order of their complexity, and form a hierarchy from rational mechanics to sociology, of which Comte and so many others vainly endeavour to make a simple social mechanics. The destiny of this universal objective science is to progress for ever without ever being completed; for it is of the same nature as number--that is to say, essentially indefinite and imperfect. It not only finds an inexhaustible subject of study in the external world; it encounters a mystery impenetrable to its methods and analyses in the very subject that creates it, and which, in creating it, remains outside the mechanism it sets in motion. In fact, when the thinking subject considers itself, or considers things in relation to itself, it brings to bear upon itself and them a second series of judgments of an altogether different character. It estimates them and it estimates itself according to a _norm_ which is in itself. It declares them to be good or bad, beautiful or ugly, rich or poor in life, harmonious or discordant. In other words, it is no longer the idea of number--it is the category of _the good_ which becomes the necessary form of these new judgments, which, for this reason, are called judgments of _estimation_ or of dignity, and it is clear that between these two kinds of judgments there is no common measure. They can no more encounter each other than two balls rolled on different planes.