It would be hasty to assume, in the present state of the evidence and after man's very brief and very ill-conducted reflective experience, that a gradual convergence of views even upon the prior questions cannot be hoped for. The principal vicissitudes, and the outcome of the contemporary revolt against dualism seems to the author to have put people in a position to give a fairly definite and confident answer to this hypothetical question. The logical elements which so many philosophers, since this century began, have been trying to synthetize into a coherent body of doctrine, refuse to combine. The probative force of such a survey of the results of these attempts of representative realistic philosophers to escape dualism depends, it is true, upon whether the actual attempts may fairly be supposed to exhaust the logically possible ways of going about the business.