Mind and body are parts of the whole of life. And we begin to understand their reciprocal relations in that whole. The life of man is the life of a moving being, and it would not be sufficient for him to develop body alone. All moving beings, however, can foresee and reckon up the direction in which to move; and this fact makes it necessary to postulate that they have mind. This foreseeing the direction of movement is the central principle of the mind.
