  The intuitive idea is that the qualifying feature is a concept, empirically acquired by the perceiver, and now used to categorise the object perceived. To see that the passing animal is a horse, one must first possess the concept horse, by means of previous acquaintance with the type. (Use of the term ‘concept’ here does not imply that the features are in any sense subjective—for the Nyāya they are objective entities or constructions out of objective entities). The Nyāya thus use their theory of memory (initial experience causing dispositional trace causing memory event) as a theory of concept-possession.