AN empirical science is either one which, as the term implies, is supported by the evidence of the senses, or one which is built up out of the elements of experience. Physical science, beginning and ending in sensory phenomena, is an example of the first kind; psychology an example of the second. But the ordinary use of the term ‘empirical’ limits experience to that of a sensory nature. My plea is that this limitation is an arbitrary one and due to a philosophical prejudice. There is more in experience than sensory elements. Apart from the self and its states, affective and volitional, there are thought-things as well as sensed-things, relations as well as elements, correlates as well as original fundaments, in experience. The universe of physical science, for example, consists of thought-things; it is a conceptual universe erected on the foundations of a sensed one.