In Perception, H. H. Price undertakes an examination of existing theories of perception, rejecting what is bad, retaining what is good, and adding original reflections to construct a new, more adequate theory avoiding the difficulties of the old. Price phrases the problem of perception in two separate questions:1. What is perceptual consciousness and how is it related to sensing? 2. What is the relation of “belonging to” when we say a sense-datum “belongs to” a thing?
Consciousness contains givens—color expanses, pressures, noises, smells. These givens are sense-data, and the act of apprehending them intuitively is sensing. There are other data of consciousness, such as of introspection or memory. Sense-data differ from these solely in that they lead us to conceive of and believe in the existence of material things (whether or not such things actually do exist). By accepting sense-data as given, we do not commit ourselves to believing (1) that they persist when not being sensed (but only that they exist when sensed), (2) that the same sense-datum may be a datum of more than one mind, (3) that sense-data have some particular status in the universe, or (4) that they originate in any particular way.