ABSTRACT
In the permanence of an object, conserved during its temporary disappearance, Piaget sees the first manifestation of a conservation of individual identity. The ‘identify’ applies both to a single object class and to a class of equivalence of multiple objects. ‘Identity’ is used as much in respect of an individual who remains the same person, in spite of real or apparent changes, as it is with regard to two or more objects, distinct and separate but exactly similar. Perceptual constancies provide an example of when the identity of a particular object is maintained across modifications of its context: changes in the spatial relationships between the object and the subject and changes in illumination. The identity of an object and its intrinsic properties is conserved despite modifications in proximal stimuli corresponding to different levels of illumination or different positions of the object. Relationships of identity or equivalence are therefore only distinguished by the exhaustiveness or otherwise of the possibilities of substitution.
