The ‘Only Possible Argument’ of Kant: A Critical Reconstruction

In his precritical period Kant developed a demonstration of the existence of God that he believed to be the only possible one. Whether this argument is valid is a much-disputed question. To give an answer to this question I will reconstruct Kant’s argument with the means of modern logic and semantics and show which are—in my view—it’s weak points. To achieve this, I will use a combination of the formalism of predicate-, propositional and modal logic without, thought, introducing such a combined logic.