to medicine agriculture also forms a root for biology as well as for chemistry.
Psychology in early times had an indistinct origin in metaphysics, but as an inductive science it is of recent growth. In addition to the metaphysical problems which the study of mental processes was supposed to solve, two practical problems may be mentioned as stimulating the development of psychology. First the study and treatment of pathological mental states, which unites psychology with biology and chemistry in that all three have their origin to some extent in medicine. Secondly, the study of normal mental states and the course of mental development in order to improve the intellect and ameliorate human conditions through better methods of education.
As biology rests on the attempt to heal individual disease, so sociology arises from the desire to cure social ills and improve social relations. This statement would not be true of all the social sciences, especially economics, which found its chief incentive in the attempt to increase the material wealth of one social group at the expense of other groups. The general science of sociology, however, like that of biology, had its chief root in the desire to heal. The existence of poverty, crime, labor disputes, and similar problems has stimulated the desire to understand the principles of human association and the laws of social development.
With this brief review of the social origin of the sciences, we are prepared to consider in greater detail their effects upon social progress. In order to do this it will be advantageous to separate the sciences into three groups by diagonal lines, so to speak, the divisions not corresponding to the recognized boundaries of the different sciences. The first group includes astronomy, the greater part of physics and smaller parts of chemistry and biology. This group comprises what may be called the sciences of the environment. The second group includes a small part of physics and larger portions of chemistry, biology and psychology. This group comprises the sciences pertaining to individual life. Sociology and a part of psychology form the third group, treating of social life. If a larger number of the subsciences are included, the divisions would not be materially altered. A part of economics would be included in group one, as dealing with the environment; and a part of geology would fall into group two. These three groups may be designated for the sake of brevity as the natural sciences, the biological sciences and the social sciences, dealing respectively with the environment, with individual life, and with social life.
The historical development of the sciences is a complicated problem. Comte maintained that they developed in a serial order from the simplest to the most complex in the order of his classification—astronomy, physics, chemistry, biology and sociology. Spencer strongly opposed this theory and produced many facts to show that the serial