It is almost unnecessary to add that the most complete positivism pervades these books from one end to the other. We owe to M. Sixte some sentences which express with extreme energy this conviction that everything in the mind is there of necessity, even the illusion, that we are free. “Every act is only an addition. To say he is free, is to say that there is in the total more than there is in the sum of all the parts. That is as absurd in psychology as it is in arithmetic.” And again: “If we could know correctly the relative position of all the phenomena which constitute the actual universe, we could, from the present, calculate with a certainty equal to that of the astronomers the day, the hour, the minute when England, for example, will evacuate India, or Europe will have burned her last piece of coal, or such a criminal, still unborn, will assassinate his father, or such a poem, not yet conceived will be written. The future is contained in the present as all the properties of the triangle are contained in its definition.” Mohammedan fatalism itself is not expressed with more absolute precision. “With speculations of this order, only the most frightful aridity of imagination would seem to comport. Thus that which M. Sixte so often said of himself: I take life on its poetic side,” appeared to those who heard it the most absurd of paradoxes. And yet nothing is truer with regard to the special nature of the minds of philosophers. What essentially distinguishes the born philosopher from other men is that ideas instead of being formulas of the mind more or less exact, are to him real and living things. Sensibility, with him, models itself upon the thought instead of establishing a divorce more or less complete, between the heart and the brain, as with the rest of us. A Christian preacher has admirably shown the nature of this divorce when he uttered this strange and profound sentence: “We _know_ well that we shall die, but we do not _believe_ it.” The philosopher, when he is one by passion and by constitution, does not conceive this duality, this life divided between contradictory sensations and reflections. This universal necessity, this indefinite and constant metamorphosis of phenomena, this colossal work of nature ceaselessly making and unmaking itself, with no point of departure, no point of arrival, by the play of the primitive cells alone, this parallel work of the human mind reproducing under the form of thoughts and volitions the movement of physiological life, was not for M. Sixte a simple object of speculation.