Abstract

FROM the point of view of scientific investigation no two subjects could present a stronger contrast than the two named in the title of this book. Movement is the ultimate fact of physical science. The measurement of the direction and velocity of movements is the most satisfactory achievement of science, and the scientist is contented with his explanation of any natural phenomenon when he has reduced it to movements and expressed their relations in a mathematical formula. On the other hand, nothing could be less attractive to the scientific investigator with such an aim than the domain of mental imagery, the world of imaginary objects. Mental images are not only removed from general observation and open to direct study only by the individual who experiences them, but even he has no satisfactory way of measuring them and reducing them to mathematics.