Nor is the matter made any clearer by saying that the "health" of society is the end we ought to promote.[249] This has been put forward as an interpretation of the hedonistic principle, which brings that principle into accord with the theory of evolution. As such, however, it seems open to fatal objections. Given as an explanation of "pleasure," it falls back upon the notion of "life"; for health can only be defined as that which conduces to continued and energetic life. Further than this, there is a special difficulty in adopting health as the proximate end where pleasure is the ultimate end. Even if we could assert that health always leads to pleasure, it is not evident that it is better known, or more easily made the end, than pleasure. For of present pleasure we have a standard in our own consciousness from which there is no appeal. And, although the value of a series of pleasures is much harder to estimate, there is also no slight difficulty in saying what will promote the efficiency or health of an organism. Besides, the question arises whether health really corresponds with pleasure; and this is, in another form, the question which has been already answered in the negative,--whether life can be measured by pleasure. [Sidenote: or falls back on the notion of life.] On the other hand, if "health" is to be taken not as an explanation of or means to pleasure, but as a substitute for the notion of "life," then we hardly get beyond our original terms. "Health" must be interpreted simply as that which leads to strong and continued life: so that the only information to be got from the new term is that the life we are to promote must be vigorous and long; and this was already implied in saying that it is the increase or development of life that is the end. It will not do to identify the notion with the mere balance of physiological functions which, in common language, appropriates to itself the term "health." We must include the health of the soul as well as the health of the body, and the health of society as well as the health of the soul. The balance of mental and social, as well as of physiological, functions, is implied in the complex life of whose evolution we form a part. To say that we are to promote this balance of various functions, is to say nothing more than that we are to promote the life into which physical and mental and social factors enter. The attempt to arrive at an end for conduct, by consideration of the characteristics of evolution, has been made without success. It has been found, too, that "development" or "increase of life" does not admit of translation into the language of hedonism: and the question thus arises, how we are to define this end, which we are unable to interpret in terms of pleasure. [Sidenote: Ways of determining increase of life or natural good,]