Explain Kant's approach to the concept of existence in the pre-critical periodBased on the book«The only Possible Argument in Support of a Demonstration of the Existence of God».

 Kant has considered the question of existence in both pre-critical and critical periods. In the pre-critical period, he discussed the issue of existence in his treatise "«The only Possible Argument in Support of a Demonstration of the Existence of God " and even pointed to the inability of reason to provide an existential argument to prove the existence of God; The same view that Kant developed in the critical period and expressed more fully. In addition, in the critical period, he introduced existence as one of the categories of comprehension. Kant's approach to the concept of existence in both periods was based on the distinction between real predicate and logical predicate. A real predicate is a predicate that adds anything new to its subject, and a logical predicate is a predicate that does not add anything new to its subject. It should be noted that Kant's approach to existence in the critical period has not changed much, and The only difference with the pre-critical period is that in the critical period, he expressed his views on existence based on the categories of understanding and distinguishing synthetic / analytic theorems; As some of Kant's commentators, such as J. Forgie and Etienne Gilson, argue, Kant has dealt with it more fully in The Only Possible Foundation for Proving the Existence of God.