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Classification of the Sci
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unifies conduct on various occasions. The former unity is fairly objective and real; the latter involves subjective elements, and is liable to the perturbations of prejudice and fancy, greatly reducing the value of our classification of the instincts and even the enumeration of them. On any one occasion the unity of quasipurpose of an instinct lies in this, that all its action tends, upon one identical subject to superinduce one and the same character; and this in such a way that if this action is hindered in its accomplishment a new and independent line of conduct will be started tending to the same result. What is meant may be brought home to the apprehension by a case of purposeless action. If we dam a running stream, the hollow behind the dam begins to fill with water, until ultimately it overflows and the stream has its way again. But this is purposeless. For the original action simply continues, its effect