It is clear that in any sensory perception; first of all there is an interaction between the sensory equipment and the sensory quality existing in the object. The sensory quality, which is comprehended by us in our perception, is actually created as a result of bio-chemical and bio-physical interaction between the sensory quality existing objectively in the object (the external world) and the sensory equipment. Thus, the taste of an apple as perceived by us is the one which is created by the interaction between the objective taste existing in the apple and our tasting equipment, (i.e., tongue).
We may explain the above phenomenon more clearly by using simple mathematical symbols.
Let ‘O’ denote the objective quality, ‘P’ denote the perceived quality and ‘S’ denote a function representing sensory equipment. Then, in mathematical expression,
P = f (O, S).