In such manner, then, as simply and as briefly as [p.209] I find myself able to put the case, runs the theory of parallelism; with its equal reality and its non-interference of two distinct but thoroughly correspondent agencies or substances, certainly a theory of a formal, rather than genuine and vital, sympathy. Metaphysically it is dualism still persistent. But one needs only a little insight, and perhaps also a slight leaning towards the gruesome, to see that it is dualism--at least the dualism of the medieval type--already in a shroud. Even dualism demands, and should always be allowed, its funeral service and a decent burial. With the passing of dualism, however, the sympathy becomes more than merely formal. Two things always equally real cannot be really two, and a perfect parallelism, though satisfying to certain cherished traditions in philosophy or theology, is so saturated with unity as to be almost, if not quite, at the point of precipitation. Without attempting, therefore, any further appraisal of parallelism metaphysically, we may turn to what will seem more practical. Looking or thinking through this metaphysical theory we can see that it is equivalent to a declaration that the physical and the spiritual in human life, or in life at large, are meant for each other. Perhaps in a somewhat stilted fashion, but nevertheless beyond any chance of question, it is a philosophy that makes man and nature always accordant and adaptable, and coming as it did in the history of thought near the beginning of the modern period, it can lay claim to this meaning on historical as well as on logical grounds. Its value to philanthropy, too, perhaps only another sign of its modernism, is easily [p.210] detected, since it supplies just such tangible means as the material conditions of life for the accomplishment of philanthropic ends, and its service to scientific psychology, plainly an indispensable service, lies in its making the physical nature a medium, not merely for the expression, but also for the study of what is psychical. As for its relation to the argument of this book, it is simply dualism meeting; or trying to meet, the demand, in the first place, that reality itself should be indeterminate--_always a tertium quid_--and, in the second place, that the things that are definite, be they material or spiritual, should work together for reality. Under the same demand, be it said, atomism could stand only if supplemented by some doctrine of assumed unity or co-operation among all the elements--as, for example, by Leibnitz's doctrine of pre-established harmony.