Kant famously believed his transcendental method disposed of the classical project of ontology. He argued that ontology was premised on a naive epistemological assumption according to which being (the thing in itself) would immediately be available to thought. Against ontology in this sense, Kant was eager to prove that everything that exists has to be constituted by thought, given that thought can only grasp what is compatible with the logical form of referring to something, which differs from the fact of being referred to. Instead of laying out the structure of being as such, he assigned philosophy the task of reflecting on the constitution of objects qua objects of thought.
— Markus Gabriel, ‘Transcendental Ontology’
According to Camus our lives are rendered absurd by the no-knowability of whether or not there is a god; whether or not our lives have meaning (same question, different spin, not necessarily dependant on god). The question is then what to do when faced with this absurdity? Should we embrace nihilism or continue as if our lives have meaning? The conclusion of Camus’ Myth of Sisyphus is that “we must imagine Sisyphus happy.” It is not just that we must make this choice but that we can make no other. Choosing nihilism would be a meaningful reaction to conditions of absurdity because it would be our human choice. In Mearleu-Ponty’s phrase, we are condemned to meaning. (Here you can see the radical difference between Camus’ and Sartre’s Existentialism. For Satre we are condemned to be free. No such luck with Camus.) Pascal argued we should, logically, wager on God. Camus demonstrates that we have no choice but to wager on meaning. What that meaning might be we are welcome to fill out for ourselves.