Alvin Plantinga is an American philosopher who is regarded as one of the most important philosophers of religion of the present day. He taught at the University of Notre Dame (1982–2010) as John A. O’Brien Professor of Philosophy and received the Templeton Prize in 2017. His contribution to the book lies in his analytically precise critique of naturalism and in his defense of the capacity for truth of human reason.
Key Contribution: The Evolutionary Argument Against Naturalism
Plantinga’s most famous argument — the Evolutionary Argument Against Naturalism (EAAN) — shows that ontological naturalism defeats itself:
- If naturalism and evolution are true, our cognitive faculties were shaped by natural selection.
- Natural selection selects for adaptive behavior, not for true beliefs. False beliefs can lead to adaptive behavior just as well.
- On naturalistic assumptions there is therefore no reason to suppose that our cognitive faculties reliably produce true beliefs.
- But whoever doubts the reliability of his own reason undermines every one of his beliefs — including naturalism itself.
- Therefore naturalism is self-defeating: it undermines the very basis on which it is asserted.
This argument directly supports the thesis of personal ontology that the person’s capacity for truth is not a by-product of blind evolution, but is grounded in the nature of the person as a spiritual being. Only if reason is ordered toward truth — not merely toward survival — can it know the being of things.
Critique of Methodological Naturalism
In Where the Conflict Really Lies (2011) Plantinga argues that methodological naturalism — the demand that science admit only natural causes — is not a necessary condition of science, but a philosophical predecision. Newton, Kepler, and Boyle practiced science explicitly within the framework of theistic convictions. If methodological naturalism is absolutized, it easily leads to scientism: the fallacy of inferring from “science finds no supernatural causes” that there are none.
Plantinga’s core thesis: The real conflict is between naturalism and science, not between theism and science. The presuppositions of science — the order of nature, the reliability of reason, the intelligibility of the world — are better grounded by theism than by naturalism.
Warrant and Proper Function
In his Warrant trilogy (Warrant: The Current Debate, 1993; Warrant and Proper Function, 1993; Warranted Christian Belief, 2000) Plantinga develops an epistemology based on the notion of proper function: a belief has epistemic warrant when it is formed by cognitive faculties that are functioning properly, in an environment for which they were designed, according to a design plan aimed at truth.
This approach presupposes that the human being’s cognitive faculties are designed for truth — a thesis that cannot be grounded on naturalistic assumptions (EAAN), whereas on theistic assumptions it follows naturally.
Concept of Person
Plantinga holds a substance dualism: the person is an immaterial substance that is connected with the body but not identical with it. In “Against Materialism” (2006) he argues that materialist theories of mind cannot cope with the unity of consciousness and with mental causation.
This substance dualism is compatible with the substance-ontological concept of person of the book, but differs in method: Plantinga argues analytically and modally (I could exist without my body, therefore I am not identical with it), whereas the Thomistic tradition understands the person as a body-soul unity in the sense of hylomorphism.
Place in the Book
Plantinga’s EAAN forms an analytic complement to the ontological critique of naturalism by Spaemann and Seifert. While Spaemann argues ontologically (persons are substances, not bundles of functions) and Planck criticizes positivism from within natural science, Plantinga shows on the epistemic level: naturalism undermines the condition of the possibility of all cognition — and thereby of itself.
Sources: Bexten 2017, pp. 218–254 (theoretical oblivion of the person and naturalism).
Further sources:
- Plantinga, Alvin (2011): Where the Conflict Really Lies: Science, Religion, and Naturalism. New York: Oxford University Press.
- Plantinga, Alvin (1993): Warrant and Proper Function. New York: Oxford University Press.
- Plantinga, Alvin (2000): Warranted Christian Belief. New York: Oxford University Press.
- Plantinga, Alvin (2006): “Against Materialism”. In: Faith and Philosophy 23, pp. 3–32.
- Beilby, James K. (ed.) (2002): Naturalism Defeated? Essays on Plantinga’s Evolutionary Argument Against Naturalism. Ithaca, NY: Cornell University Press.