From No Subject - Encyclopedia of Lacanian Psychoanalysis
L'objet petit a can thus be defined as a pure parallax object: it is not only that its contours change with the shift of the subject; it only exists - its presence can only be discerned - when the landscape is viewed from a certain perspective. More precisely, the object a is the very CAUSE of the parallax gap, that unfathomable X which forever eludes the symbolic grasp and thus causes the multiplicity of symbolic perspectives. The paradox is here a very precise one: it is at the very point at which a pure difference emerges - a difference which is no longer a difference between two positively existing objects, but a minimal difference which divides one and the same object from itself - that this difference "as such" immediately coincides with an unfathomable object: in contrast to a mere difference between objects, the pure difference is itself an object. Another name for the parallax gap is therefore minimal difference, a "pure" difference which cannot be grounded in positive substantial properties.
- The Parallax View.</span> </li> </ol>