[T]hus scientific meteorology explains the thunder-storm by inserting this phenomenon into a larger group of homogeneous phenomena. In other words, it recognizes lightning as an electric spark, and then searches after the conditions of its origin, i.e., the processes which precede and accompany electrical expansion and discharge in the atmosphere.
Science has the same task to perform in relation to states of consciousness. It has to seek their uniform antecedent and concomitant phenomena in order thus to determine the lawful relation of these phenomena. The antecedent and concomitant phenomena, are, as experience shows, physiological processes in the brain and nervous system. Accordingly, it is the business of science to substitute for the pseudo-science " psychology " and its prescientific principles, " soul" and " psychic forces," the natural-scientific explanation. Scientific psychology is physiology.
This gives us the formal principle. As regards the matter itself we may go further and say: The so-called states of consciousness, proclaimed as peculiar and unparalleled states, are in reality nothing of the kind. Science can see in them only peculiarly modified movements; psychical states as such, regarded objectively, are nothing but physiological processes. (p. 62)
That constitutes a fairly concise and compact statement of what today we call the psychoneural identity theory, as well as that of the scientific program that follows from it (promissory materialism). Elsewhere Paulsen takes a swipe at dualism:
If we wish to refer the ontological view of popular thought to a class, we shall have to call it Vague Dualism. Bodies constitute the real reality, but alongside of them there exists a reality of the second order, bodily beings without real corporeality, that are both active in the bodies as efficient forces, and also exist for themselves as departed spirits.
The philosophical conception of reality is, as was mentioned before, characterized by the tendency to Monism. It is the fundamental impulse of philosophic thought to derive reality from one principle, to reduce the different forms of being to one original form. Two kinds of ontological monism result, according as we proceed from the facts of the external, visible world, or from those of the inner world; namely, Materialism, and Spiritualism. The former asserts : Bodies and movements constitute thn original form of reality: these also explain the facts of perception, thinking, and willing. Spiritualism or Idealism, on the other hand asserts: The facts of inner life as presented in self-consciousness are the first and only reality; thoughts cannot be conceived as products of matter, while matter may be conceived as the product of thought; the corporeal world is phenomenal. (p. 54f)
As his is a textbook in philosophy, it should remind us that what we have been discussing are primarily philosophical problems, not scientific ones. Since the publication of this book countless similar texts have covered the same material ad nauseam. What purpose is served by repeating the same positions over and over again? If we have something new to argue, that successfully refutes a philosophical position, we should make it clear what new element it is that we are contributing--and make certain that it is a new element, and not just a new version of an existing position that can be generally accepted (or not) or is prone to a general criticism (JMHO). I therefore recommend that each of us read the relevant several pages in Paulsen's book keeping that in mind: http://books.google.com/books?ei=pC6yTM-mEpTmsQOa0rDwCw&ct=result&output=text&id=v_E0AAAAMAAJ&dq=scientific+%22lawful+relation%22&q=vague+dualism#v=snippet&q=vague%20dualism&f=false
Now what is most interesting is that Paulsen was evidently an adherent of panpsychism!