Final answer:
The debate on whether God exists typically involves ontological arguments, like those of Anselm, which assert necessary existence as part of the concept of God. Kant counters this by asserting that existence cannot simply be attributed to a concept without empirical evidence, challenging the validity of ontological proofs and impacting the philosophical basis of atheism.
Step-by-step explanation:
The question of whether God exists has been debated through various ontological arguments, particularly those initiated by Anselm, and critiqued by philosophers like Kant. Anselm's approach was to use a reductio ad absurdum strategy, suggesting that God, being the greatest conceivable being (GCB), must exist, as the concept would be contradictory if God existed only in the mind.
However, Kant objected to this ontological argument, arguing that existence is not a predicate; that is, one cannot confer existence upon a concept simply by including existence within the definition of the concept. For Kant, existence must be verified through experience, not merely asserted a priori. This position fundamentally challenges the ontological argument for God's existence by suggesting that affirming the concept of God as existing does not necessitate actual existence.
Moreover, Anselm's argument that one must think of the GCB as existing, and Descartes' assertion that conceiving an all-perfect being requires thinking of that being as existing, do not, according to Kant, confirm actual existence. They represent mental exercises lacking empirical validation. Atheism, in this philosophical context, is the absence of belief in a deity, neither based on ontological naivety nor necessitating concrete refutation of a deity's existence, but rather on the absence of empirical evidence of such existence.