How did Alvin Plantinga develop the divine sense within the framework of Reformed epistemology, and what new elements did he add?

Alvin Plantinga — the analytic philosopher at the University of Notre Dame then Calvin College — presented in his epistemic trilogy "Warrant" (1993-2000) and his book "Warranted Christian Belief" (2000) an advanced philosophical development of the concept of "sensus divinitatis" (divine sense) within the framework of Reformed epistemology. This development moved the concept from Calvinist tradition to the heart of contemporary philosophical debate.

Inadequate Responses to Avoid

From some believers:

"Plantinga proved God's existence through the divine sense." A fundamental error. Plantinga does not use the divine sense as proof for God's existence, but as a defense of faith's rationality if God exists. His argument is defensive, not offensive.

"The divine sense makes rational arguments unnecessary." A harmful oversimplification. Plantinga does not reject rational arguments, but proposes that faith can be warranted even without them. This is a different epistemic position from rejecting arguments.

From some objectors:

"Plantinga is merely a disguised fideist." An accusation lacking precision. Plantinga is a rigorous analytic philosopher, and his arguments are technical and sophisticated. His theory of knowledge (proper functionalism) is independent of his religious considerations and is discussed in purely epistemic literature.

"The divine sense is an unscientific concept." A confusion of levels. Plantinga does not present the divine sense as a scientific hypothesis, but as an epistemic possibility within a philosophical theory of knowledge.

Why These Responses Are Inadequate

They share a failure to understand the precise structure of Plantinga's project. He is not trying to "prove" anything, but to dismantle a specific epistemic objection: that religious belief is irrational because it lacks sufficient evidence.

Background: Reformed Epistemology

Reformed Epistemology — developed by Plantinga with Nicholas Wolterstorff and William Alston — challenges "Classical Foundationalism" which proposes that warranted beliefs must be:
- self-evident
- or incorrigible
- or inferred from these foundations

Plantinga argues that Classical Foundationalism is self-defeating: it is neither self-evident nor incorrigible nor derivable from self-evident truths or incorrigibles. Therefore, we need a broader criterion for warranted basic beliefs (properly basic beliefs).

Plantinga's Concept of the Divine Sense

Plantinga borrows from Calvin the concept of "sensus divinitatis" — an innate cognitive faculty that produces beliefs about God in certain contexts. But he develops it philosophically:

First: Epistemic Framework. The divine sense is not an "argument" but a "cognitive faculty" like memory or sense perception. Just as memory produces beliefs about the past without inference, the divine sense produces beliefs about God without inference.

Second: Proper Function Theory. A belief is warranted if:
- it results from a cognitive faculty functioning properly
- in an environment suitable for its operation
- according to a reliable design plan aimed at truth

If God exists and created us with a divine sense, then beliefs produced by it are warranted.

Third: Triggers and Responses. The divine sense is triggered by:
- Contemplating nature → belief "God created this"
- Feeling guilt → belief "God is displeased with me"
- Severe danger → belief "God protects me"
- Overwhelming beauty → belief "This is from God"

These beliefs arise directly, not as products of inference.

New Elements Added by Plantinga

1. Philosophical Technique. He moved the discussion from theology to contemporary analytic epistemology. He used tools of analytic philosophy (precise distinctions, formal arguments, conceptual analysis).

2. Distinction between Justification and Warrant. "Justification" is an internal concept relating to epistemic responsibility. "Warrant" is an external concept relating to objective connection to truth. The divine sense provides warrant if it functions properly.

3. Extended Aquinas/Calvin Model. In "Warranted Christian Belief," he developed a detailed model for how Christian knowledge works, including:
- The divine sense (natural knowledge of God)
- Internal testimony of the Holy Spirit (knowledge of revelation)
- The role of sin in disrupting cognitive faculties

4. Epistemic Defense. He showed that the objection "faith is irrational" assumes that God does not exist. If God exists, then faith is perfectly rational. The objection is circular.

Main Objections and Responses

Religious Diversity Objection: If the divine sense is reliable, why is there religious disagreement?

Plantinga's response: Sin has impaired the divine sense. Diversity does not negate original reliability, just as eye diseases do not negate the reliability of vision.

Reliability Objection: How do we distinguish genuine divine sense from delusion?

Plantinga's response: The same question applies to sense perception and memory. We lack an independent external criterion, but this does not negate their reliability if they are properly designed.

Self-Validation Objection: Could not any belief claim to result from a special "sense"?

Plantinga's response: Not all claims are equal. The divine sense has a long history, wide distribution, and coherence with our other cognitive faculties.

Plantinga's Place in Contemporary Debate

Plantinga's project changed the map of contemporary philosophy of religion. Before him, debate was confined to "Is there sufficient evidence for belief?" After him, it became "What does sufficient evidence mean? And do we need it at all?"

Critics (Fales, Martin, Gale) see that Plantinga has not solved the problem of religious diversity. Supporters (Wolterstorff, Alston, Evans) see that he provided a coherent epistemic framework for rational faith.

Later Developments (2000-2026)

The "Extended Reformed Epistemology" movement (Crisp, Rea) applies Plantinga's insights to other theological issues. The "Reformed Epistemology Critique" movement (Schellenberg, Draper) develops more sophisticated objections. The "Integration with Cognitive Psychology" movement (Barrett, Clark) searches for empirical foundations for the divine sense in psychology of religion.

Where We Stand in This Debate Today

Plantinga's project succeeded in changing the terms of debate. The question is no longer "Is faith rational without evidence?" but "What is the nature of rationality and evidence?" Even critics accept that Plantinga showed that faith can be rational under certain conditions.

But the deeper question remains: Are these conditions actually fulfilled? Does the divine sense exist? Plantinga does not claim to answer this question philosophically, but is content to show that answering yes is not irrational.

For Advanced Reading

- Advanced level: Plantinga's theory of Warrant
- Advanced level: Religious diversity objections to Reformed epistemology
- Alvin Plantinga, Warranted Christian Belief (Oxford UP, 2000)
- Alvin Plantinga, "Reason and Belief in God" in Faith and Rationality (Notre Dame, 1983)
- James Beilby (ed.), Naturalism Defeated? (Cornell UP, 2002)
- Michael Bergmann, "Rational Religious Belief without Arguments" in Philosophy Compass (2007)
- "Family: Sensus Divinitatis and Reformed Epistemology" page on the website