Alvin Carl Plantinga (born November 15, 1932) is analytic philosopher, known for his work in philosophy of religion, epistemology, metaphysics and apologetics. Some of his arguments include the modal ontological argument, evolutionary argument against naturalism, the possibly best possible world theodicy, and reformed epistemology. His critics have claimed he is a supporter of intelligent design, although he denies this saying he is rather a Christian creationist. 
He is the author of numerous books including God and Other Minds, The Nature of Necessity, Warranted Christian Belief, and Where The Conflict Really Lies.
Possibly the best possible world theodicy
In response to the problem of evil, Alvin Plantinga argue for the possibility that God could not have created a better world. Therefore, an omnipotent and omnibenevolent God may possibly be compatible with evil. Since they are possibly compatible, the axioms of the problem of evil do not imply a contradiction. 
- "It is possible that God, even being omnipotent, could not create a world with free creatures who never choose evil. Furthermore, it is possible that God, even being omnibenevolent, would desire to create a world which contains evil if moral goodness requires free moral creatures."
- "The fact that free creatures sometimes go wrong, however, counts neither against God's omnipotence nor against His goodness; for He could have forestalled the occurrence of moral evil only by removing the possibility of moral good."
Fine tuner of the Universe
- "One reaction to these apparent enormous coincidences is to see them as substantiating the theistic claim that the Universe has been created by a personal God and as offering the material for a properly restrained theistic argument—hence the fine-tuning argument. It's as if there are a large number of dials that have to be tuned to within extremely narrow limits for life to be possible in our Universe. It is extremely unlikely that this should happen by chance, but much more likely that this should happen, if there is such a person as God."
Argument from other minds
- Main Article: Argument from other minds
In God and Other Minds, Plantinga argued that it is difficult to prove other minds exist. Similarly, the existence of God is also difficult to prove. Since both views are equally credible despite of the difficulty and the existence of other minds is generally accepted, it is plausible that god exists.
- "If my belief in other minds is rational, so is my belief in God. But obviously the former is rational; so, therefore, is the latter. [...] What I argued, in essence, is that from this point of view belief in other minds and belief in God are on an epistemological pare. In neither case are there good arguments of the sort required; hence if the absence of such arguments in the theistic case demonstrates irrationality, the same goes for belief in other minds."
- Main Article: Conceptualist argument
"How could there be truths totally independent of minds or persons?... How could the things that are in fact true or false—propositions, let’s say—exist in serene and majestic independence of persons and their means of apprehension? How could there be propositions no one has ever so much as grasped or thought of?"
- — Alvin Plantinga
Evolutionary argument against naturalism
- Main Article: Evolutionary argument against naturalism
- "The problem begins in the recognition, from this point of view, that the ultimate purpose or function of our cognitive faculties, if they have one, is not to produce true beliefs, but to promote reproductive fitness. What our our minds are for (if anything) is not the production of true beliefs, but the production of adaptive behavior. [...] it does not guarantee or even suggest that our belief- producing processes are reliable, or that our beliefs are for the most part true. [...] But if [naturalism together with evolution] can't be rationally accepted, there is indeed a conflict between naturalism and evolution: one cannot rationally accept them both."
- Michael Ruse, Alvin Plantinga and Intelligent Design, December 14, 2011, Chronical of Higher Education
- Alvin Plantinga, God, Freedom, and Evil, 1974
- Alvin Plantinga, "The Dawkins Confusion; Naturalism ad absurdum," Christianity Today, March/April 2007.
- The Evolutionary Argument Against Naturalism by Alvin Plantinga, in Science and Religion in Dialogue, edited by Melville Y. Stewart.
- Some of Plantinga's essays (From the Virtual Library of Christian Philosophy)