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242 throughout past ages lay the promise now read by its fulfilment in the history of species. All this is clearly admitted, and our gratitude to Darwin is proportionate.

Spencer's task lies in a different field, where a much more perplexing work is to be done. Possibly we ought to allow that Darwin's task, as the pioneer's, was much more difficult than we now recognize. The honors bestowed upon him, in some measure obscure the times of perplexity through which he passed. But, admitting this to the utmost, the difficulties to be encountered in making out man's place in nature are much greater. Darwin's modes of observation are insufficient here. As long as we can see with our eyes the whole facts to be explained, definite conclusions are more readily reached. When we get beyond this line of evidence, difficulties increase. As compensation, it is true on the other hand, that we have full opportunities for study of our own nature. Thus far, evidence is at command both of investigator and critic, much more readily than when observations are concerned with animal life. Great as this advantage is, however, it is more than counterbalanced by the special difficulties attendant upon research into the conditions of moral and spiritual life. Even to reach the problems, we pass beyond questions of structure and form, and applications of physical law. There are, indeed, some who claim that physiology includes this whole inquiry; but theirs is only a fond belief, not a scientific induction. Impressions from without do not explain our moral life. The most enthusiastic workers in the field of physiological research have failed to make good their contention. The testimony of Clifford is unexceptionable here. Thinking differs so essentially from the known functions of organism, that it is impossible to indicate its characteristics without showing how far apart it is from muscular movement, and from life-results which can be secured by supplies of wholesome food, such as sustains bodily vigor. Even with the wonderful advances of recent years, thought remains a mystery to the physiologist. This is the barrier standing in the way of the Evolution Theory.