Abstract
This paper gives account of Peirce's semiotic thinking about God from the perspective of his life-long dispute with Kant's doctrine of the Ideal of Pure Reason. My examination will proceed upon showing how Peirce deals with Kant's three theses presented in the Ideal, namely that (i) the idea of God is a necessary condition of the totality of objects' determination (A573=B601ff.), but (ii) is at the same time empty, or "problematic", i.e. non-representative (A328/B384), and (iii) knowledge of God is impossible (A578=B606ff.).
Thus I explain Peirce's early (1859, W 1: 37-43) argument that (contrary to ii) God is a possible object of representation, and later (1908, EP 2: 434-450) argument (against iii) for God's reality, considering Musement, Peirce's conception of experience and Objective Idealism. Finally, the question whether and in what way Peirce would accept (i) will be answered by analyzing his theory of Retroduction and Aesthetic Ideal.