Moses Mendelssohn's Original Modal Proof for the Existence of God

In Morning Hours (1785), Moses Mendelssohn presents a proof for the existence of God from the grounding of possibility. Although Mendelssohn claims that this proof is original, it has not received much attention in the secondary literature. In this paper, I analyze this proof and present its historical context. I show that although it resembles Leibniz’s proof from eternal truths and Kant’s precritical possibility proof, it has unique characteristics that can be regarded as responses to deficiencies Mendelssohn identified in these earlier proofs. I argue that by analyzing the semantics of judgments about dispositions, Mendelssohn provides a novel explanation for the basic premise shared by these proofs, namely that possibility is grounded in actuality. Additionally, this analysis simplifies the inference to a unique infinite mind grounding all possibility. Thus, the proof is worth studying both for historical reasons and for its original account of modal concepts.