There is, however, another aspect of the question. Let us suppose the unknown got rid of; or to be more precise,—and if we regard with M. de Roberty the psychic centres as special receivers in which the cosmical energy empties itself, resolving itself into sensation and idea, and from whence it spreads itself anew as motion,—let us suppose that we have summed up all the energies received and emitted, and verified the law which reduces memory to the conservation of energy; let us suppose in fine that philosophy shall have found in the ego the synthesis of the non-ego, expressed “in symbolic abbreviations and in signs,” and shall have realised the “logical monism” which reduces things to their ideas: would the intellect—and would the sensibility—even then be completely satisfied? Can we conceive a state in which the curiosity of man as to all that concerns himself will be at rest, and when he will cease to be disquieted about the cause of suffering and of life? Kant long ago propounded this question. But, according to M. de Roberty, the thinker who is “a prey to the afflux of emotion referred to by Kant,” the man “given over to the desire for another kind of knowledge than that of experience,” are, in the category of intellectual emotions, diseased and “perverted” persons. “The sentiments, so varied in aspect and in strength, which inspire us,” writes he, “the contemplation of the unknown, determine the mental illusion which materialises, so to say, our ignorance and transforms the unknown into the unknowable.” Would it be inconsistent, however, to preserve the emotion of the unknown without “materialising” it, without pronouncing any dangerous scientific _ignorabimus_? M. de Roberty does not accept this situation,—which was that of Littré. I do not know whether any one will discover the “vaccine,” as he calls it, “of the pessimist emotion which has produced agnosticism or latent religiosity.” If this constitutes a mental malady, I fear much that it will be incurable. As long as there is unhappiness in life, there will also be unsatisfied curiosity, and for a very long time to come, inquietude. * * * * *