senses, special See FACULTY PSYCHOLOGY. sensibilia (singular: sensibile), as used by Russell, those entities that no one is (at the moment) perceptually aware of, but that are, in every other respect, just like the objects of perceptual awareness.
If one is a direct realist and believes that the objects one is aware of in sense perception are ordinary physical objects, then sensibilia are, of course, just physical objects of which no one is (at the moment) aware. Assuming (with common sense) that ordinary objects continue to exist when no one is aware of them, it follows that sensibilia exist. If, however, one believes (as Russell did) that what one is aware of in ordinary sense perception is some kind of idea in the mind, a so-called sense-datum, then sensibilia have a problematic status. A sensibile then turns out to be an unsensed sense-datum. On some (the usual) conceptions of sense-data, this is like an unfelt pain, since a sense-datum’s existence (not as a sense-datum, but as anything at all) depends on our (someone’s) perception of it. To exist (for such things) is to be perceived (see Berkeley’s ‘esse est percipii’). If, however, one extends the notion of sense-datum (as Moore was inclined to do) to whatever it is of which one is (directly) aware in sense perception, then sensibilia may or may not exist. It depends on what – physical objects or ideas in the mind – we are directly aware of in sense perception (and, of course, on the empirical facts about whether objects continue to exist when they are not being perceived). If direct realists are right, horses and trees, when unobserved, are sensibilia. So are the front surfaces of horses and trees (things Moore once considered to be sensedata). If the direct realists are wrong, and what we are perceptually aware of are ‘ideas in the mind,’ then whether or not sensibilia exist depends on whether or not such ideas can exist apart from any mind.
See also PERCEPTION , RUSSEL. F.D.