The main idea runs somewhat as follows. The interest of the Unconscious is opposed to our own; it would be to our advantage not to live, it is to the advantage of the Unconscious that we should do so, and that others should be brought into existence through us. The Unconscious, therefore, in the furtherment of its aims, has surrounded man with such illusions as are capable of deluding him into the belief that life is a pleasant thing, well worth the living. The instincts that are within us are but the different forms beneath which this unreasoning desire to live is at work, and with which the Unconscious inspires man and moulds him to its profit. Hence the energy so foolishly expended for the protection of an existence which is but the right to suffer, hence the erroneous idea which is formed of the pain and pleasure derivable from life, and hence the modification of past disenchantments through the influence of fresh and newer hopes. With regard to happiness, there are, according to Hartmann, three periods or forms of illusion, from all of which the world must be thoroughly freed before the great aim of science can be attained. The first of these illusions consists in the idea that under certain circumstances happiness is now obtainable on earth; the second, in the belief that happiness is realizable in a future state; and the third, in the opinion that happiness will be discovered in the march of progress through the coming centuries. Of these three ideas, the first has for some time past been recognized by many as a chimera. In certain quarters the decomposition of the second has already begun, but the belief in the reality of the third is unquestionably the paramount conviction of the present century. When each of these three illusions has been utterly routed and universally done away with, then, Hartmann considers, the world will be ripe for its great quietus. The first of these three forms is, of course, the most tenacious; indeed, it is an incontestible fact that man, even when miserable, clings to life, and loves it not only when there is some vague hope of a brighter future, but even under its most distressing conditions. It is, therefore, against this illusion that pessimism, to be successful, must rain the hardest blows. The views of many eminent writers on this subject have already been expressed in the course of these pages, but their views, while in a measure important, should nevertheless be received with a certain amount of caution, for they emanate from superior minds, in which melancholy as the attribute of genius constantly presides.