Man upon Earth, Parts i.-viii., 1854-55.] proclaimed the approach of an ideal society in which there will be no ignorance, no poverty, and no charity--a system "which will ensure the happiness of the human race throughout all future ages," to replace one "which, so long as it shall be maintained, must produce misery to all." His own experimental attempt to found such a society on a miniature scale in America proved a ludicrous failure. It is to be observed that in these socialist theories the conception of Progress as indefinite tends to vanish or to lose its significance. If the millennium can be brought about at a stroke by a certain arrangement of society, the goal of development is achieved; we shall have reached the term, and shall have only to live in and enjoy the ideal state--a menagerie of happy men. There will be room for further, perhaps indefinite, advance in knowledge, but civilisation in its social character becomes stable and rigid. Once man's needs are perfectly satisfied in a harmonious environment there is no stimulus to cause further changes, and the dynamic character of history disappears. Theories of Progress are thus differentiating into two distinct types, corresponding to two radically opposed political theories and appealing to two antagonistic temperaments. The one type is that of constructive idealists and socialists, who can name all the streets and towers of "the city of gold," which they imagine as situated just round a promontory. The development of man is a closed system; its term is known and is within reach. The other type is that of those who, surveying the gradual ascent of man, believe that by the same interplay of forces which have conducted him so far and by a further development of the liberty which he has fought to win, he will move slowly towards conditions of increasing harmony and happiness. Here the development is indefinite; its term is unknown, and lies in the remote future. Individual liberty is the motive force, and the corresponding political theory is liberalism; whereas the first doctrine naturally leads to a symmetrical system in which the authority of the state is preponderant, and the individual has little more value than a cog in a well-oiled wheel: his place is assigned; it is not his right to go his own way. Of this type the principal example that is not socialistic is, as we shall see, the philosophy of Comte. CHAPTER XIII. GERMAN SPECULATIONS ON PROGRESS 1.