increase while the other diminished, sometimes the reverse, and again both vary together. Rather we should suspect separate processes, psychic and physical, for such variation. And if both processes are separate and independently based, why speak of quale? Or why hunt for some mode of accounting for this particular separate kind of sensation known as pain, other than a mode like that by which we account for all other kinds of sensation; namely, by specific neural activities related to particular modes of stimulation?
That so many kinds of influence cause pain has been used as a proof of its being a general attribute. But we know too little of the final physical process of any sense to give basis to this argument. The same air wave may cause a sound, a 'cold creep,' a feeling of jar, of tickle, of pain, of teeth-on-edge, and perhaps more. But there is no knowing what molecular variations, all dependent on the sound wave, these different sensations were finally correspondent to. It will be a main point, relative to certain doctrines in this discussion, that pain and pleasure are subject to more kinds of influences than the other senses. But this will always mean that more transformations lead up to the final specific form or physical basis of each. In so far as I know, no one denies that pains do come from the same outer influences as give us sight, sound, touch, and so on. There are two main theories for explaining this. One, the traditional doctrine, makes a single nerve mediate, we will say, the touch and the pain or pleasure. The other, the specific energy doctrine, gives to each sensation a separate nerve. The outer influences are the same for both theories, and the resulting feelings are the same. The differences, then, of the theories mainly concern the modes of mediation. Now if we hold to the law, "like effects, like causes," we must say that the physical activities correspondent to a touch or to any other specific sensation must be the same in kind always. To abandon this position is to abandon all sense or reason for any physical basis of mind at all. Therefore as we have every reason to believe that the touch feeling is the same, whether pleasurable or painful, the physical activity concomitant to the touch should also
