The distinction between the necessary and the contingent, the de jure and the de facto, or the a priori and a posteriori, is often treated as if it were an objective one, something about or in the cosmos, somewhere in the borderlands between the subject matters of mathematics and of physics, or between metaphysics and physics. In fact the distinction only makes sense for consciousness and belongs to its very structure, so you cannot ask about the necessity or contingency of the purported fact of consciousness without begging the question. Normally it seems that the subject, bolstered by a pre-reflective cogito, belongs on the side of the necessary while the perceived world is the domain of contingency, but this is the exact inverse of deeper insight reveals. The subject, the experiencing consciousness is entirely contingent, as is the world, which is only the subject's experience, and what is necessary in contrast to this, is the subject's contingency. You are a necessarily contingent being - which is much the same as seeing the truth of the Buddhist notion of emptiness (of self-nature). This is because you are not your own foundation. There is a deeper insight beyond this, but it can only arise on the ground of a full realisation of the meaning of necessary contingency. Ordinary consciousness approaches this to the extent that it surrenders its fatuous claims to, or project towards, its own necessity, it claim to de jure existence.