Faith and Reason Part 6: Plantinga

Mark Hansard continues his series on Faith and Reason, exploring a key twentieth- and twenty-first century philosopher. For the previous entries in the series, and other work by Mark, click here

Alvin Plantinga (1932-    ), is a contemporary Christian philosopher who has had an enormous impact on modern philosophy of religion in the areas of metaphysics, epistemology, and arguments for God’s existence. For many years he was the John A. O’Brien professor of philosophy at Notre Dame. He received his Ph.D. in philosophy from Yale University in 1958.

Plantinga has singlehandedly changed the debate in several areas of analytic philosophy. In his first book published in 1967, God and Other Minds, he argued that believing in the existence of God was just as rational as believing in other minds. The critical reception of the book was overwhelmingly positive, and one reviewer claimed it was “one of the most important to have appeared in this century on the philosophy of religion.”[1] In God, Freedom and Evil (1974),[2] he argued for a version of the free will defense for the problem of evil.[3] Using modal logic,[4] he argued that it is possible that in any possible world God could have created with free will in it, people would always have freely chosen to sin.[5] Because of these arguments, Plantinga is widely regarded to have changed the debate on the problem of evil in analytic philosophy.[6]

In epistemology as well, Plantinga has changed the debate with his Reformed Epistemology, a philosophical view which allows that belief in God is rational without evidence.[7] We will conduct a brief overview of Plantinga’s view here. In order to understand his view, we need to understand classical foundationalism, a major theory of knowledge that precedes Plantinga’s modification.

According to classical foundationalism, most propositions I believe, I believe based on evidence. But there are foundational propositions as well, foundational in the sense that they are the starting points for my belief structure. And I believe these latter propositions not because I have evidence for them, but simply because I can “see” they are true. Propositions such as “2+2=4” are foundational because once I understand what the numerals mean, the proposition is obviously true to me. My belief “there is a tree” is formed simply because “I am being appeared to treely,” and thus I immediately form the belief, without inference, that the tree is there (I do not, for example, reason to myself that “if I see the image of a tree there, there must be a tree there.” I form the belief immediately, without evidence). These foundational beliefs are called “properly basic beliefs.” Thus, on classical foundationalism, all my beliefs are either properly basic, or they are deduced, inferred, or otherwise reasoned from these properly basic beliefs. Locke allowed, for example, that propositions with probabilistic evidence, or propositions that constituted testimony, could be rationally believed if they traced their foundations all the way down to properly basic beliefs.[8]

Plantinga’s move with Reformed Epistemology is to argue that belief in God is properly basic. In his magisterial work Warranted Christian Belief,[9] Plantinga argues it is not necessary to have evidence God exists, rather, we believe he exists simply because, given the proper circumstances, we automatically form the belief God exists, or we simply “see” he exists. For example, suppose I am on a hike in the Rockies, and as I turn a corner, I am overwhelmed by the sudden majesty of Longs Peak. The belief “God exists” is immediately formed in me as I see the mountain. I do not infer God’s existence because the mountain needs a Creator. I simply immediately “know” God is there because of my experience. My belief in God is properly basic. This is the first surprising move Plantinga makes.

Is my belief in God under such circumstances truly rational? The second surprising move on Plantinga’s part is to explain that yes, it is, because it is formed under a belief-forming mechanism that was designed by God to work this way. By doing this, Plantinga brings a Christian view of justification and “warrant” into the debate in epistemology. He claims that something like John Calvin’s sensus divinitatis is correct.[10] Plantinga defines the sensus divinitatis as a divinely created cognitive mechanism for forming belief in God under the proper circumstances, such as feelings of guilt or gratitude, or experiencing the beauty of nature. Plantinga claims not only that we are rational to believe in God under these circumstances, but our beliefs can constitute knowledge because, if they are true, and they were formed under the correct belief-forming mechanism which was triggered in the correct way, according to God’s design, they would constitute knowledge.[11] Thus for Plantinga, “warrant” is this rational process under which a person forms beliefs under the correct mechanism, triggered in the correct way, according to God’s design. And he believes our beliefs in God constitute warranted true belief if God exists. In other words, they constitute knowledge of God independent of evidence. Of course, there remain evidential arguments for God’s existence, Plantinga says, and they may be worth pursuing. But they are not rationally necessary to believe in God.

Notice then, that, if Plantinga’ view of warranted belief in God is true, then I am rational to believe in God unless there are de facto objections to my belief in God: objections to such beliefs based on facts. Plantinga thus answers the de jure objection to Christianity which says that, even if Christianity were true, it would be irrational to believe. In sum, he argues that there is nothing rationally hindering my belief in God if I formed the belief he exists in the properly basic way in the correct circumstances. Plantinga concludes then, that there is not a de jure objection to belief in God that is independent of a de facto objection to such a belief. I am rational to believe in God this way unless there are (other) facts that demonstrate belief in God is false.[12]

Plantinga’s original thinking has engendered quite a bit of literature and several objections, the most famous being “the Great Pumpkin Objection.” Critics argue that if belief in God could be properly basic, so could a host of other beliefs, such as belief in the Great Pumpkin. Since, on Plantinga’s view, testimony can constitute a properly basic belief, Linus’ belief in the Great Pumpkin is justified because he’s been told by his parents the Great Pumpkin exists. But his belief would not be warranted because Linus’ parents are lying, and thus his belief based on their testimony would not be a properly basic belief: it would not be formed correctly in the proper circumstances. Thus his belief doesn’t constitute knowledge. The fact that Linus’ belief would be justified does nothing to compromise Plantinga’s theory, since his theory is based on warrant, and Linus doesn’t have warrant in this case. It’s worth remembering here that Plantinga’s project is not to show Christianity is true, but to show that, if it were true, it would be rational to believe.

Thus, with Reformed Epistemology, Plantinga has created a view which defines warrant, defines when a person has warrant with regard to what she believes, and then shows that, if Christianity is true, a model for a Christian having warrant with regard to her beliefs in God is rationally defensible. While there have been critiques of Plantinga’s view, so far the critiques are not substantial enough to not rationally hold it. In my next post, we will look at Plantinga’s “Evolutionary Argument against Naturalism.”


[1] Michael Slote, The Journal of Philosophy, Vol. 67, No. 2 (Jan. 29, 1970), 39-45.

[2] Alvin Plantinga, God, Freedom and Evil (1977 ed., Harper & Row), chapter 4.

[3] The logical problem of evil goes like this: The following four propositions contain a logical contradiction: 1) God is omniscient. 2) God is omnipotent. 3) God is omni-benevolent. 4) Evil exists.

[4] For more on modal logic, see the Stanford Encyclopedia of Philosophy on modal logic:

[5] Plantinga calls this “trans-world depravity.”

[6] In fact, many philosophers believe Plantinga has solved the logical problem of evil. Robert Adams says, “It is fair to say that Plantinga has solved this problem. That is, he has argued convincingly for the consistency of God and evil.” See Howard-Snyder, Daniel; O’Leary-Hawthorne, John (August 1998): “Transworld sanctity and Plantinga’s Free Will Defense.” International Journal for Philosophy of Religion. 44 (1): p. 1. Other philosophers who share such a view include William Alston, Chad Meister, and William L. Rowe.

[7] For the discussion here I am relying mainly on J.P. Moreland and William Lane Craig, Philosophical Foundations for a Christian Worldview (Downer’s Grove, IL: InterVarsity Press, 2nd Ed. 2017), 147-55.

[8] For more on Locke’s view, see Faith and Reason Part 4: Locke. Locke’s view is a very interesting contrast to Plantinga’s, and this of course is deliberate on Plantinga’s part.

[9] Warranted Christian Belief (Oxford: Oxford University Press, 2000). This work is the third in a trilogy on warrant. The other two volumes are: Warrant: The Current Debate (Oxford, Oxford University Press, 1993), and Warrant and Proper Function (Oxford: Oxford University Press, 1993).

[10] John Calvin: “There is within the human mind, and indeed by natural instinct, an awareness of divinity…A sense of divinity which can never be effaced is engraved upon men’s minds” (John Calvin, Institutes of the Christian Religion, 1.31.1, 3).

[11] Plantinga goes on to extend the sensus divinitatis model to specifically Christian beliefs, by claiming that the Holy Spirit can form immediately beliefs in specifically Christian doctrines when a person reads Scripture, for example. Such beliefs would also be properly basic. This is an intriguing extension of the model, but there is not space here to say more about it. See Warranted Christian Belief, chapter 8.

[12] In chapters 11-14 of Warranted Christian Belief, Plantinga’s project is to consider “defeaters, ” propositions that, if true, would make belief in God irrational, even if such a belief were held in the properly basic way. He considers some of the more popular scholarly defeaters, and concludes they are not substantial enough to override the rationality of the sensus divinitatis.

Print Friendly, PDF & Email

Mark Hansard

Mark is on staff with InterVarsity Christian Fellowship in Manhattan, Kansas, where he ministers to Faculty at Kansas State University and surrounding campuses. He has been in campus ministry 25 years, 14 of those years in faculty ministry. He has a Master's degree in philosophy and theology from Talbot School of Theology, La Mirada, CA, and is passionate about Jesus Christ and the life of the mind. Mark, his wife and three daughters make their home in Manhattan.

More Posts


    Keith B. Miller commented on June 29, 2019 Reply

    I discuss aspects of the free will defense in the context of the problem of natural evil. I draw primarily on John Polkinghorne, Holmes Rolston III, and W. H. Vanstone in arguing that giving freedom is an act of a self-emptying and cruciform God. For those interested, the article is Keith B. Miller, 2011, “‘And God saw that it was good’: Death and pain in the created order,” Perspectives on Science and Christian Faith, v.63, no.2, p.1-10.

    andrewymoon commented on June 30, 2019 Reply

    I am a professor of philosophy at Virginia Commonwealth University, and reformed epistemology is one of my research specialties. For those who are interested in learning more about reformed epistemology, see this podcast, where I was interviewed on some recent work on reformed epistemology.

      Bob Trube commented on July 18, 2019 Reply

      Thanks Andrew!

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.