of criticism. Where they are clearly stated they are inadequate. Where they resort to figures of speech and tell us about the two sides of the shield, or the convexity and concavity of the same curve, as illustrations of the ultimate oneness of nature amid the various manifestations of experience, there these efforts merely sink back into the primitive incoherency so dear to all pre-Kantian metaphysics. The same curve is, indeed, convex and concave; but matter and spirit are simply not the two faces of a curve, and the relevant circumstance on which this metaphor turns will never be clear to us until we learn, quite literally, wholly apart from fables about shields, just how, in what sense, and by what evidence, matter and mind are known to be of like substance. And that we must do, ere this hypothesis can have for us a religious value. The failure of dogmatic Monism, if it should take place, ought, indeed, not to throw us over into the arms of an equally dogmatic Dualism; but we must refuse to accept the monistic hypothesis until it has been freed from all trace of mysticism. We shall here follow the plan announced at the outset of the chapter, and confine our attention to the realistic Monism, that regards the events in the external world as the results of the action of the one Power. A very different form of monism we shall ourselves hereafter maintain. But just now we deal in negations.
Let us begin with the attempts that have been made to interpret the results of modern physical science in a monistic sense, by regarding the ultimate physical or chemical units as endowed with some
