The Overmind has been defined as an Ocean of Stable Lightnings & the Supermind as integral Vision.
We are always bothered about the Contraries or Contradictions which co exist in Reality. This is known as the Law of Coincidence of Opposites !
For, Truth, like the atom , is the Organic Unity of Opposed Parts.
Irreconcilable contrariety is the nature of the mental Reason. To the Overmental, they are coexistent correlatives. And to the Supramental, they are an Integral Whole !