Ontology via Contrast: a proposition concurrent with Objectivism?

Ontology via Contrast — the idea that, at a fundamental level, 

entities exist entirely through contradistinction within the plenum universe.

A is A because of non-A  

Last month's blog was entitled ‘Questioning Objectivism: how come A is A’? 

In further pursuit of this question, here's a link to Objectivism Online Forum and my first post there expanding upon this core ontological issue.

I'm awaiting any response there to fathom if Objectivist metaphysics refutes such a proposition 

or whether it remains an open possibility. 

NB, I no longer call this proposition ‘the 4th law’ as it steps beyond the pure axiomatic validation of the three classical laws of thought.