Carnap and Quine both argue that treating metaphysical "existence" as a predicate leads to a number of problems. In particular, they argue that it is not possib

Carnap and Quine both argue that treating metaphysical "existence" as a predicate leads to a number of problems. In particular, they argue that it is not possible to know what exists independently of our own perceptions and experiences. This means that any claims about the existence of things beyond our own experience are necessarily speculative and cannot be known for certain.