It might be objected that even though pleasures differ in kind, a comparison and summation of them might be possible, just as comparison and summation of weights is possible, although weight depends not on bulk alone but also on specific gravity. It cannot be denied that some numerical expression for qualities of pleasure may yet be found, by which they may be compared. But it is to be noted that, the higher we go in the scale of existence, the more distinct becomes the growth of a principle of selection or distribution which the members of a combination must follow in order to produce a given quantitative result. In chemistry we may obtain the atomic equivalent of sulphuric acid (98) in many ways, but we can obtain the acid itself only by specific combinations in specific proportions. In determining what food to give an animal, we must consider not bulk alone but the nutritiousness of various sorts. We might express the nutritiousness of various foods by numbers, but the numerical equivalent would tell us nothing, unless we knew the kinds of food to be combined. And in the same way we might express the sum of pleasures as end numerically, but until we know the kinds of activities and so of pleasures to be combined to this sum, the formula is useless to inform us as to the end or method of attaining it. The popular conception of happiness avoids all the difficulties and perplexities caused by setting up pleasure as the end, because in that conception pleasures and pains are never considered apart from conduct and character. Thus, though the end involves pleasure, the criterion is good conduct. The good conduct necessarily involves pleasure, for conduct which only outwardly conforms to the moral rule, and in which the agent does not take pleasure, is not really good. The pleasure-formula thus represented as the standard of conduct is to be distinguished, as actual ethical pleasure in the act, from the pleasures attendant on the act as results, and which may be termed pathological in a Kantian sense. The ethical pleasure need not be unmixed, for the act which satisfies one part of a man's nature does not necessarily satisfy all the other parts. But the ethical pleasure must be present as the total reaction of character considered apart from the incidentals of result.