A CLASSIFICATION OF FEELINGS. 333 transition from one conspicuous feeling to an adjacent con- spicuous feeling, and therefore imperatively demands a place in a classification of feelings. The fact that the scheme here set forth necessitates an inclusion of cognitions in the classi- fication of the feelings, so far from militating against it, is actually evidence in its favour. The great difference between feelings and relations between feelings when subjectively viewed i= the duration ; and I have already shown how, as cognitions become more and more complex, they become more prolonged, so that while every cognition is in one aspect a feeling, this aspect becomes more and more con- spicuous as cognition becomes developed. Hence there is the more reason for indicating the position that such feelings occupy at the root of the classification. The way in which an interaction is initiated, as it is a necessary element in all interactions whatever, is a fortiori a necessary element in all interactions between the organism and its environment ; and every group of interactions that is constituted on any other principle must necessarily be sus- ceptible of division according to the way it is begun. There is, however, a set of divisions of very different character, which, although they are applicable only to the special group of interactions with which we are now concerned those between the organism and its environment are based on a principle that, in reference to these interactions, is of primary importance. They are based on the principle of Evolution. To announce to a botanist or a zoologist that the classi- fication of plants or of animals ought to conform to their genealogical kinships, and therefore to harmonise with and illustrate the principle of Evolution, would be as idle and superfluous as to persuade an astronomer of the truth of the law of Gravitation. The matter has passed out of the region of discussion. It has become an accepted doctrine a truism. The great majority of modern psychologists admit that the human organism has come into existence and reached its present condition by a similar process of evolu- tion, and that by this process has originated and developed not only the physical organism but the mind also. Those who admit the development of mind by evolution, should therefore not need, any more than the botanist or the zoologist, a laboured demonstration that the states resulting from this process should be classified in accordance with it. For those who do not admit that the principle of evolution applies to mental phenomena, this paper is not intended. It does not appeal to them ; it has no claim to their con-