ABSTRACT
The method of doubt proceeded by questioning, in the first place the veracity of sense-perception, and in the second the self-evidence of clear and distinct ideas. Reflexion along the lines produces the theory of representative perception. This chapter explains that the theory of representative perception was strongly established in the introspective Augustinian tradition, and had been put forward by innovating scientists like Galileo as a consequence of their separation of primary and secondary qualities. The theory of representative perception presupposes a real and independent knowledge of extension, and immediately that support is withdrawn it becomes meaningless. Moreover, the mediation which the percept undergoes when it passes from the physical to the mental sphere accounts for the distortion which a comparison between percept and intuition shows it to have experienced. As extension stands to the body, as spirit stands to the soul, so perception and feeling stand to the new substance, body-soul or soul-body.
