The general and fundamental motives of the revolt which people are to consider are intelligible enough; and it is impossible not to sympathize with them. It might or might not prove in the end logically possible to escape from dualism - without giving up realism; but there were at least strong reasons for wishing to escape from it. General preconceptions as constituted not only intelligible but reasonable grounds for desiring and hoping for overthrow of the hypothesis of ideas, and the establishment in its stead of a form of realism monistic in its theory of perceptual and other knowledge, and affirming the non-mental status of sensory and other data. The importance of keeping distinct the grounds of epistemological and those of psychophysical dualism has been emphasized in the first lecture. While misconceptions of the dualist's arguments had no small part in causing the revolt, the new movement perhaps owed not less to sheer lapses of memory on part of philosophers.