What is there, then, in political economy that is necessary and true; whither does it tend; what are its powers; what are its wishes? It is this which I propose to determine in this work. What is the value of socialism? The same investigation will answer this question also. For since, after all, socialism and political economy pursue the same end,--namely, liberty, order, and well-being among men,--it is evident that the conditions to be fulfilled--in other words, the difficulties to be overcome--to attain this end, are also the same for both, and that it remains only to examine the methods attempted or proposed by either party. But since, moreover, it has been given thus far to political economy alone to translate its ideas into acts, while socialism has scarcely done more than indulge in perpetual satire, it is no less clear that, in judging the works of economy according to their merit, we at the same time shall reduce to its just value the invective of the socialists: so that our criticism, though apparently special, will lead to absolute and definitive conclusions. This it is necessary to make clearer by a few examples, before entering fully upon the examination of political economy. % 2.--Inadequacy of theories and criticisms. We will record first an important observation: the contending parties agree in acknowledging a common authority, whose support each claims,--SCIENCE. Plato, a utopian, organized his ideal republic in the name of science, which, through modesty and euphemism, he called philosophy. Aristotle, a practical man, refuted the Platonic utopia in the name of the same philosophy. Thus the social war has continued since Plato and Aristotle. The modern socialists refer all things to science one and indivisible, but without power to agree either as to its content, its limits, or its method; the economists, on their side, affirm that social science in no wise differs from political economy. It is our first business, then, to ascertain what a science of society must be. Science, in general, is the logically arranged and systematic knowledge of that which IS. Applying this idea to society, we will say: Social science is the logically arranged and systematic knowledge, not of that which society HAS BEEN, nor of that which it WILL BE, but of that which it IS in its whole life; that is, in the sum total of its successive manifestations: for there alone can it have reason and system. Social science must include human order, not alone in such or such a period of duration, nor in a few of its elements; but in all its principles and in the totality of its existence: as if social evolution, spread throughout time and space, should find itself suddenly gathered and fixed in a picture which, exhibiting the series of the ages and the sequence of phenomena, revealed their connection and unity. Such must be the science of every living and progressive reality; such social science indisputably is.