How did Alvin Plantinga argue that belief in God can be properly basic?

In the context of the philosophy of religion, Alvin Plantinga challenged the classical foundationalist view that a belief is only rational if it is either self-evident, incorrigible, or supported by other beliefs.

Plantinga argued that this standard is self-referentially incoherent, as the claim itself is not self-evident or supported by evidence. Instead, he proposed that belief in God can be "properly basic"—meaning it is rational to hold the belief without inferential support from other propositions. He likened this to how we accept other basic beliefs, such as the existence of the past or the existence of other minds, which are triggered by specific circumstances or experiences rather than derived from a chain of logical arguments. By categorizing belief in God as properly basic, Plantinga sought to demonstrate that theistic belief does not require a formal proof to be considered intellectually responsible or justified.