The possible existence of a metaphysical realm beyond or above the sensory world

I first became interested in philosophy in high school when I realized one day that all space is the same size; it is only the material boundaries encompassing it that differ. After that there came to me the realization (which I found later in Hume) that causality is a perception in the observer and not a datum of external reality. In college I was given Plato to read and thereupon became aware of the possible existence of a metaphysical realm beyond or above the sensory world. I came to understand that the human mind could conceive of a realm of which the empirical world was epiphenomenal. Finally I came to believe that in a certain sense the empirical world was not truly real, at least not as real as the archetypal realm beyond it. At this point I despaired of the veracity of sense-data. Hence in novel after novel that I write I question the reality of the world that the characters' percept-systems report.

Philip K. Dick