forms are inevitably formed. The laws of mental association necessitate these primitive notions of transmutation, of metamorphosis, of duality; and, until experiences have been systematized, no limits or restraints are known. With the eyes of developed knowledge we look at the snow as a particular form of crystallized water, and at hail as drops of rain which congealed as they fell. When these become fluid we say they have thawed—thinking of the change as a physical effect of heat; and, similarly, when the hoar-frost fringing the sprays turns into hanging drops, or when the surface of the pool solidifies and again liquefies. But, looked at with the eyes of absolute ignorance, these are transmutations of substance—passings from one kind of existence into another kind of existence. And in like ways are necessarily conceived all the changes above enumerated.
Let us now ask what happens in the primitive mind when there has been accumulated this heterogeneous assemblage of crude ideas, having, amid their differences, certain resemblances. In conformity with the law of evolution, every aggregate tends to integrate, and to differentiate while it integrates. The aggregate of primitive ideas must do this. After what manner will it do it? At the outset, these multitudinous vague notions form a loose mass without order They slowly segregate, like cohering with like, and so forming indefinitely-marked groups. When these groups begin to form a consolidated whole, constituting a general conception of the way in which things at large go on, they must do it in the same way: such coherence of the groups as arises must be due to some likeness among the members of all the groups. We have seen that there is such a likeness—this common trait of duality joined with this aptitude for passing from one mode of existence to another.
Integration must commence by the recognition of some conspicuous typical case. It is a truth perpetually illustrated, that accumulated facts lying in disorder begin to assume some order if an hypothesis is thrown among them. When into a chaos of detached observations is introduced an observation akin to them in which a causal relation is discernible, it forthwith commences assimilating to itself from this heap of observations those which are congruous, and tends even to coerce into union those of which the congruity is not manifest. One may say that as the protoplasm forming an unfertilized germ remains inert until the matter of a sperm-cell is joined with it, but begins to organize when this addition is made, so a loose aggregate of observations continues unsystematized in the absence of an hypothesis, but under the stimulus of an hypothesis undergoes changes bringing about a coherent systematic doctrine. What particular example, then, of this prevalent duality plays the part of an organizing principle to the aggregate of primitive ideas? We must not look for an hypothesis properly so called: an hypothesis is an implement of inquiry not to be framed by the primitive mind. We must look for some experience in
