There is a very close resemblance between the views of the two great popularisers of the nineteenth century. Just as Büchner, to show the stupidity of the idea of eternal life, repeated the legend of the “Wandering Jew,” so Haeckel, with the same object, related the legend of the unhappy “Ahasuerus” who sought death vainly, finding his eternal life intolerable. “However gloriously we may depict this eternal life in paradise, in the end it would be a fearful burden to the best of men.” While there is no doubt but that such ideas are shared by many men who rely on scientific arguments, there are others to whom the problem presents itself differently. The German physiologist, Du Bois Reymond, after reflecting on the general problems of knowledge and the universe, proclaimed an “Ignorabimus” as a warning that a whole series of problems of the highest importance to humanity were outside the range of human knowledge and incapable of solution. These problems were precisely the seven “riddles of the universe” that Haeckel claimed to have solved in his book. Many learned men think that the great problems, those, according to Tolstoi, that constitute the only true science, can never be solved. “Every day there comes a new conquest,” said Richet,[285] “but we are no nearer solution of the ultimate enigma, the destiny of human life, an enigma probably never to be solved.” Philosophers have taken the same view. “It cannot be from science,” said Guyau, “that personality is to require the proofs of its own durability.”[286] The answers given by science as it exists to-day, have failed to console the spirits that have applied to her. When Richet, in the discussion on the “bankruptcy of science” recalled the discovery of treatment of diphtheria by specific serums as an instance of the value of scientific research, Brunetière replied, “Serum therapy cannot prevent us from dying, nor tell us why we must die.” The problem of death always recurs. What is the use of saving the life of a child smitten by diphtheria only that it may grow up, and by learning the inevitability of death become filled with terror? If science be really powerless before the gravest problems that torture mankind, if she has to excuse herself by admitting her incompetence, if she can do no better than to extol the silent annihilation of the grave, it is not surprising that many minds and these not the least capable, turn from her. The desire to find some consolation in the miseries of a purposeless existence throws them into the arms of religion or metaphysics. Here lies the explanation of the actual return in these days to faith. People plunge into mysticism hoping to find there something more comforting than the annihilation offered by science.