Nearly any culture in the world would recognize the Two Elements, which for simplicity here I will call "Structure" and "Energy". The pair of them in concert make up everything that exists, and many dualities are just different lenses on their underlying nature - order and chaos, logic and passion, ice and fire, potential and kinetic, divide and choose, and so on. They are not antithetical, and certainly not antagonistic, any more than voltage is the enemy of current (one of the better examples of their manifestation). Rather, they are two sides of the same endlessly-spinning coin, and all of existence is their dance. I am sure you are already intimately and instinctively aware of the pair of them.
The Two Nonelements, on the other hand - "Oblivion" and "Hallucination"1 - are rather trickier to comprehend. (Indeed, Oblivion is in some sense defined by its incomprehensibility.) Unlike the complementary pair of Structure and Energy, Oblivion and Hallucination are fundamentally irreconcilable - neither exists, but in exactly opposite ways. Together they account for everything that does not exist. They can be loosely and inaccurately described as "that which is fundamentally impossible to think about" and "that which is fundamentally only possible to think about", respectively. For example, the idea of "the experience of being unable to experience things" is Hallucination, whereas the experience of being unable to experience things is Oblivion. (Many notions of the afterlife are simply an attempt to paper over Oblivion with a comfortable layer of Hallucination.) The set of all even integers is a Hallucination, whereas the set of all sets that do not contain themselves (specifically, the set itself, not merely the idea of such a set) dwells in Oblivion.
1Early philosophers sometimes called the nonelements "Paradox" and "Tautology", but this caused much confusion and consternation because nobody could agree on which was which. The notion of "something that doesn't exist because it is defined by its nonexistence" could be, and was, extensively argued to fall under both.
