Such a contradiction is inevitable when an attempt is made to define humanly this theory of science, of knowledge, whose end is in itself, of knowing for the sake of knowing, of attaining truth for the sake of truth. Science exists only in personal consciousness and thanks to it; astronomy, mathematics, have no other reality than that which they possess as knowledge in the minds of those who study and cultivate them. And if some day all personal consciousness must come to an end on the earth; if some day the human spirit must return to the nothingness--that is to say, to the absolute unconsciousness--from whence it sprang; and if there shall no more be any spirit that can avail itself of all our accumulated knowledge--then to what end is this knowledge? For we must not lose sight of the fact that the problem of the personal immortality of the soul involves the future of the whole human species. This series of contradictions into which the Englishman falls in his desire to explain the theory of a science whose end is in itself, is easily understood when it is remembered that it is an Englishman who speaks, and that the Englishman is before everything else a man. Perhaps a German specialist, a philosopher who had made philosophy his speciality, who had first murdered his humanity and then buried it in his philosophy, would be better able to explain this theory of a science whose end is in itself and of knowledge for the sake of knowledge. Take the man Spinoza, that Portuguese Jew exiled in Holland; read his _Ethic_ as a despairing elegiac poem, which in fact it is, and tell me if you do not hear, beneath the disemburdened and seemingly serene propositions _more geometrico_, the lugubrious echo of the prophetic psalms. It is not the philosophy of resignation but of despair. And when he wrote that the free man thinks of nothing less than of death, and that his wisdom consists in meditating not on death but on life--homo liber de nulla re minus quam de morte cogitat et eius sapientia non mortis, sed vitæ meditatio est (_Ethic_, Part IV., Prop. LXVII.)--when he wrote that, he felt, as we all feel, that we are slaves, and he did in fact think about death, and he wrote it in a vain endeavour to free himself from this thought. Nor in writing Proposition XLII. of Part V., that "happiness is not the reward of virtue but virtue itself," did he feel, one may be sure, what he wrote. For this is usually the reason why men philosophize--in order to convince themselves, even though they fail in the attempt. And this desire of convincing oneself--that is to say, this desire of doing violence to one's own human nature--is the real starting-point of not a few philosophies.