This _quale_ hypothesis as presented by Marshall in _Pain, Pleasure and Aesthetics_, is set upon the dangerous foundation of ignorance, viz., of the neural basis of pleasure-pain, and of causes of its variability. It is as yet disputed whether a nerve organ for pleasure-pain has been found; but if one is generally acknowledged, the theory would be overthrown. Greater intensity in any psychosis, as sensation of warmth, means simply greater nervous activity in the particular nerves subserving the psychosis, in this case the temperature nerves. So also pleasure-pain as general concomitant like intensity must mean merely some general mode of nervous activity as yet unknown, if we allow it any nervous basis at all. Again, the variability of pleasure-pain for a given content, the fact that the taste of olives is at one time pleasant, at another, unpleasant, suggests that pleasure-pain is like intensity merely a general quality, which must in one form or another attach to all psychoses. But this does not explain anything. What we want to know is why in any given case we have pleasure and not pain; we do not wish to be put off with a general statement that the nature of pleasure-pain is such that we may have either, which is akin to the old metaphysical method of abstract explanation; making the _rationale_ of the lion leoninity is not unlike the hypothesis that explains pleasure-pain in all its variations by variability as its nature. We have a scientific faith that variability is not a general unexplainable quality, but that there is for every case of pleasure-pain a definite _rationale_ based in the facts of life demand and life history. That olives now give pleasure, and now give pain, is based upon definite conditions of physical state which are very complex, but which can be revealed by patient research alone.