We can of course reverse this relation. Then we come to the result, that psychical regularity lies outside the law of energy, and in that case it would have no sense to place this psychical energy between two other physical energies and then attempt a measurement. Such a measurement is a pure fiction. We might just as well take any other fictitious process, say a miracle, and place it in the series of transformations. These applications of physical laws to psychical phenomena are not based upon empirical facts, but they arise from a metaphysical principle, namely, the demand for a monistic view of life. Now this idea certainly has a justification, inasmuch as it rests upon a logical demand which it seeks to satisfy. If the so-called monism does not do this, it changes into a real dualism, as would clearly happen in the above-suggested rationalistic explanation of a miracle. In fact monism is only scientifically justified in its view of the relation between psychical and physical, as long as it emphasises the fact that the human being can just as little be considered a purely physical as a purely psychical being, and that man must be considered a psycho-physical individual, as we in reality experience him. This monism alone corresponds to the facts, A dualistic separation of soul and body, even if it sails under a monistic flag in the form of an atom-soul, or of an anonymous psychical energy, is a hypothesis which cannot be proved and which is useless for the interpretation of mental life. From the standpoint of the scientific and only justifiable monism, the mental processes are considered inseparable components of human and animal life. They must be judged according to the qualities that are immanent in them, and not according to laws which apply to other phenomena, and in the formulation of which no regard was paid to those psychical qualities. There cannot, however, be the least contradiction in the idea that physical and psychical phenomena follow different laws, as long as these laws are not irreconcilable with the actual unity of the psycho-physical individual. In reality we cannot talk of irreconcilability in this case, because firstly, the two series of phenomena are of a disparate nature, and because secondly everywhere, where these two series of phenomena meet together in the unity of the individual, they are really, as far as we know, subject to a principle of regular arrangement. Thus, for example, the law of creative resultants is not the least contradiction to the law of the conservation of energy, because the measures by which we determine psychical values cannot be compared with those with which we measure physical values. We judge the psychical according to its qualitative value, and the physical according to its quantitative value. The idea of value is in its origin really psychical, and this points to the fact that in reality physical values have in themselves no real