Page:Popular Science Monthly Volume 5.djvu/437

Rh organic sciences that we know of had yet been based on it, and its application to mind was undreamed of. But with a confidence in the intuitions of reason which is one of the clearest attributes of speculative genius, and which may have its analogue in the statesman in the nerve to take the vessel of the state over a bar, Mr. Spencer assumed the provisional truth of the theory, and it might be difficult to exaggerate the extent to which his exhibition of it in Psychology has contributed to its establishment.

It was first requisite to find a generalization on which to base a synthetic Psychology. The assumption being made that mind and bodily life are but subdivisions of life in general, it was required to seek out some characteristic common to both—some characteristic of vital actions in general, and distinguishing them from non-vital actions. Applying a method which Prof. Stanley Jevons has omitted to note in his "Character of the Experimentalist," Mr. Spencer arrives at a definition of life of which the essential point is that it implies a correspondence between life and its circumstances. Here is the first notable advance—the inclusion of the environing world in the definition of the science of mind; and in this is contained the germ of Mr. Spencer's later differentiation of Psychology and circumscription of its province. If correspondence with the environment is the differentia of life, it is almost an identical proposition to assert that the degree of life will vary with the completeness of the correspondence and the complexity of the environment. An ascending synthesis accordingly finds the correspondence at first direct and homogeneous, then direct but heterogeneous, as extending in space and in time, and as increasing in specialty, in generality, and in complexity. Along with the all-sided development thus going on in the correspondences, there goes on a development in the degree in which the organs and functions of the individual are so correlated and united a to respond promptly and effectually to the answering changes in the environment. Contemplating now the correspondences in their totality, it is found that the generalization on which it was proposed to base a synthetic Psychology is established, that manifestations of intelligence are found to consist in the establishment of correspondences between relations in the organism and relations in the environment, and the preliminary assumption that life and mind are fundamentally identical is proved.

Nevertheless, though these two kinds of life are primordially the same, they are in their general aspects widely unlike, and we must inquire whence the differences arise. Instinct, Memory, Reason, Feeling, and Will, have specific differences; a science of Psychology which is based on the theory of development must determine whence these