Alvin Plantinga is a renowned contemporary philosopher known for his work in metaphysics and the philosophy of religion. His best known accomplishments include:
- His work on the modal ontological argument which, thanks also to Norman Malcolm and Charles Hartshorne, enjoyed a rebirth of interest in the 20th century.
- His "free will defense" response to J.L. Mackie's logical argument from evil.
- His "reformed epistemology" attacks on foundationalism.