From some quick research this seems to be the kernel

Something is either A or not A; there is no third. sweet, not sweet? green, not green? The determination should lead to determinateness, but in this triviality it leads to nothing.

it is said that there is no third. There is a third in this thesis itself. A itself is the third, for A can be both + A and - A.

Every concrete thing, every concrete something, stands in multifarious and often contradictory relations to everything else, ergo it is itself and some other.

Is that it, or close enough?