Does Plantinga’s Notion of Properly Basic Beliefs Reflect a Coherent Epistemology?

Alvin Plantinga’s concept of properly basic beliefs, particularly as applied to belief in God, has been invoked to defend the rationality of religious faith, such as πίστις (pistis) in Hebrews 11:1, without requiring inferential justification. This essay critically examines Plantinga’s framework, arguing that it deviates from coherent epistemology—a framework that demands beliefs be justified by evidence proportionate to their claims and subject to intersubjective scrutiny. The critique focuses on four primary deviations: properly basic beliefs permit unjustified beliefs by bypassing evidential standards, foster epistemic arbitrariness due to unclear criteria, initiate an infinite regress through the unreliability of the sensus divinitatis, and illegitimately reify epistemology into ontology. Each point is supported by a syllogism to clarify the logical structure of the argument, followed by an analysis of additional logical fallacies and epistemic weaknesses in Plantinga’s approach.

The graphic below is a rough map of the critique.

1: Permitting Unjustified Beliefs by Bypassing Evidential Standards

Plantinga argues that belief in God can be properly basic, justified without external evidence through a sensus divinitatis—a cognitive faculty producing direct awareness of God. This approach deviates from coherent epistemology because it allows beliefs to be held without evidence that can be independently verified, undermining the reliability of knowledge.

Coherent epistemology requires beliefs to be grounded in evidence that aligns with their epistemic weight. For instance, a belief like “I see a tree” is justified by direct sensory evidence, verifiable through repeated observation and intersubjective agreement. Conversely, belief in God, even if triggered by a sensus divinitatis, lacks tangible evidence or consistent verification across individuals. By deeming it properly basic, Plantinga exempts belief in God from scrutiny, permitting unjustified beliefs to be treated as knowledge. This is analogous to accepting a poker hand’s strength based on intuition without inspecting the cards—an unreliable method in rational domains.

• Syllogism:
  • ➘ Premise 1: Coherent epistemology requires beliefs to be justified by evidence that is independently verifiable to ensure reliability.
  • ➘ Premise 2: Properly basic beliefs, such as belief in God via sensus divinitatis, are justified without independent evidence, relying on subjective experience.
  • ➘ Conclusion: Therefore, properly basic beliefs deviate from coherent epistemology by permitting unjustified beliefs without evidential standards.

2: Fostering Epistemic Arbitrariness Due to Unclear Criteria

Plantinga’s framework posits that belief in God is properly basic because it arises from a cognitive faculty designed to perceive God. However, this approach lacks clear, objective criteria for determining which beliefs qualify as foundational, fostering epistemic arbitrariness and deviating from coherent epistemology.

In coherent epistemology, foundational beliefs must meet defined evidential standards to avoid arbitrariness. For example, sensory beliefs like “I see a red apple” are foundational due to their consistent verifiability across observers. In contrast, belief in God varies widely across individuals and cultures, with religious experiences attributed to conflicting deities or none at all. Without objective criteria to distinguish a reliable sensus divinitatis from imagination or cultural bias, Plantinga’s framework risks endorsing arbitrary beliefs as foundational. This is comparable to a poker player claiming a hunch about a card is foundational without evidence, leading to unreliable outcomes.

• Syllogism:
  • ➘ Premise 1: Coherent epistemology requires clear, objective criteria to justify foundational beliefs and avoid epistemic arbitrariness.
  • ➘ Premise 2: Properly basic beliefs, such as belief in God, lack objective criteria, allowing subjective or culturally influenced beliefs to be deemed foundational.
  • ➘ Conclusion: Therefore, properly basic beliefs foster epistemic arbitrariness, deviating from coherent epistemology.

3: Initiating Infinite Regress Through Sensus Divinitatis Reliability

Plantinga’s reliance on the sensus divinitatis to justify belief in God as properly basic assumes this cognitive faculty directly produces true beliefs. However, coherent epistemology requires that any cognitive faculty be assessed for reliability, leading to an infinite regress that undermines the epistemic legitimacy of properly basic beliefs.

To trust the sensus divinitatis, its reliability in producing true beliefs about God must be verified, much like testing a metal detector for accuracy in detecting coins. This requires another cognitive process (e.g., reason or experience) to assess the sensus divinitatis. However, the reliability of this assessing process must then be evaluated, initiating an infinite regress of justification with no stable endpoint. This regress leaves properly basic beliefs without a firm epistemic foundation, akin to trusting an untested device in poker to predict cards without confirming its accuracy.

• Syllogism:
  • ➘ Premise 1: Coherent epistemology requires cognitive faculties producing beliefs to be assessed for reliability to ensure epistemic legitimacy.
  • ➘ Premise 2: The sensus divinitatis, as a cognitive faculty for properly basic beliefs like belief in God, requires reliability assessment, initiating an infinite regress of assessing processes.
  • ➘ Conclusion: Therefore, properly basic beliefs via sensus divinitatis deviate from coherent epistemology due to unresolved infinite regress.

4: Reifying Epistemology into Ontology Without Evidence

Plantinga’s defense of belief in God as properly basic implies that the belief’s foundational status reflects God’s actual existence. This deviates from coherent epistemology by reifying epistemic status (a belief’s role in a cognitive framework) into an ontological claim (God’s existence) without evidence to bridge the gap.

Coherent epistemology maintains a clear distinction between epistemology (how we know) and ontology (what exists). A belief’s status as properly basic pertains to its function within one’s cognitive framework, not its truth about reality. By claiming belief in God is properly basic via a sensus divinitatis, Plantinga assumes God’s existence to justify the belief, committing a category error. This is analogous to a poker player assuming a card exists because of confidence in a hunch, without checking the deck—an ontologically illegitimate leap. Coherent epistemology demands evidence to substantiate ontological claims, which properly basic beliefs fail to provide.

• Syllogism:
  • ➘ Premise 1: Coherent epistemology requires ontological claims to be substantiated by evidence, not merely by epistemic status as properly basic.
  • ➘ Premise 2: Properly basic beliefs, like belief in God, reify epistemic status into ontological claims without evidence, assuming God’s existence to justify the belief.
  • ➘ Conclusion: Therefore, properly basic beliefs deviate from coherent epistemology by illegitimately reifying epistemology into ontology.

5: Additional Logical Fallacies and Epistemic Weaknesses

Plantinga’s framework for properly basic beliefs introduces several logical fallacies and epistemic weaknesses that further undermine its alignment with coherent epistemology.

These include:

• Appeal to Authority: The framework relies heavily on Plantinga’s philosophical authority without adequately addressing critiques, assuming the validity of properly basic beliefs without defending their epistemic rigor.
• False Analogy: Comparing belief in God to memory or sensory perception is a false analogy, as memory and sensory perception are verifiable through repeated testing and intersubjective confirmation, while belief in God lacks such validation, misrepresenting its epistemic status.
• Begging the Question: The framework assumes the sensus divinitatis is reliable because it produces belief in God, presupposing God’s existence to justify the belief, a form of circularity that fails to provide an independent basis for epistemic justification.
• Special Pleading: Exempting belief in God from evidential standards applied to other beliefs (e.g., in science or daily life) constitutes special pleading, lacking a principled reason for why faith escapes scrutiny required in rational domains.
• Unsubstantiated Assumptions: The existence and reliability of the sensus divinitatis are assumed without evidence, relying on the truth of theism to justify faith, an unsubstantiated assumption that undermines epistemic legitimacy.

Conclusion

Plantinga’s concept of properly basic beliefs, as applied to belief in God, deviates from coherent epistemology in significant ways. By permitting unjustified beliefs without evidential standards, fostering epistemic arbitrariness due to unclear criteria, initiating an infinite regress through unassessed reliability of the sensus divinitatis, and reifying epistemology into ontology without evidence, the framework fails to meet the requirements of rational epistemology. Additionally, it is weakened by appeals to authority, false analogies, begging the question, special pleading, and unsubstantiated assumptions. Coherent epistemology demands that beliefs, including faith in God, be grounded in evidence proportionate to their claims, consistent with epistemic standards applied in rational domains such as science or probabilistic reasoning.

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Testing the Sensus Divinitatis: A Rigorous Epistemic Evaluation

The sensus divinitatis, or “sense of the divine,” has been proposed by some religious philosophers as an innate cognitive faculty that allows humans to perceive or become aware of God. Its defenders argue that it operates analogously to sense perception or memory, forming a legitimate basis for religious belief. However, if such a faculty is to serve as a reliable epistemic foundation, particularly for belief in supernatural claims, it must meet the same rigorous standards demanded of any belief-forming process. This essay outlines five major requirements such a faculty must satisfy in order to be epistemically justified: empirical reliability, objective demarcation, regress resolution, ontological restraint, and logical integrity.

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1. Empirical Reliability through Testable Outcomes

For any cognitive faculty to be trusted, it must generate outcomes that are consistently verifiable and that correspond to observable reality. Just as vision and hearing are confirmed through repeated intersubjective verification, so too must any claim of divine sensing withstand empirical scrutiny.

Testing Method:
The sensus divinitatis must be subjected to controlled tests that yield falsifiable predictions. For example, if a person claims to have received divine insight that a specific event (e.g., healing from a disease or a job promotion) will occur, that outcome should be tracked and verified independently. Repeating this across many individuals and contexts allows for statistical analysis of predictive accuracy.

Philosophical Justification:
Cognitive faculties are granted epistemic trust only after consistent empirical validation. Confidence in a device that predicts playing cards, for example, arises only after repeated success under observation. Similarly, any divine sensing faculty must demonstrate predictive or explanatory reliability to avoid being dismissed as arbitrary or illusory.

Challenge:
Religious intuitions and divine insights vary dramatically across individuals and cultures. This variance undermines intersubjective reliability and suggests that cultural and psychological conditioning may be doing the epistemic work, not any reliable divine faculty.

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2. Establishing Objective Criteria for Valid Outputs

Without objective standards for what counts as a legitimate deliverance of a cognitive faculty, there is no principled way to distinguish truth from hallucination, revelation from imagination. A reliable faculty must be constrained by definable evaluative criteria.

Testing Method:
Construct a framework that measures the alleged outputs of the sensus divinitatis against independent standards—historical facts, logical consistency, and ethical coherence. If a claimed divine insight instructs someone to act compassionately, that directive should be consistent with reasoned moral frameworks and observable social benefit. If instead the insight involves cruelty or contradiction, it should be rejected.

Philosophical Justification:
Absent such criteria, one could validate any religious claim—from polytheistic visions to contradictory divine commands. This results in epistemic arbitrariness, where contradictory or incoherent claims are all treated as valid simply because someone “feels” them to be divine. A standard is only useful when it can distinguish between truth and error.

Challenge:
Cultural diversity in divine claims leads to persistent disagreement. Without an agreed-upon framework to evaluate these outputs, the faculty becomes indistinguishable from culturally shaped intuition, undermining its claim to objective insight.

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3. Resolving the Infinite Regress Problem

A faculty cannot be justified if it requires another faculty to validate it, and that second faculty in turn requires another, and so on indefinitely. This infinite regress must be halted through some method of independent verification.

Testing Method:
Rather than justifying the sensus divinitatis by reference to further unverified faculties, its reliability must be anchored in observable, independently confirmed outcomes. For example, a claimed divine prompting to find lost objects or predict future events can be verified through third-party observation and documentation. This is similar to how memory is validated through photographs, notes, or the testimony of others.

Philosophical Justification:
No one would trust a new card-sensing device in poker that claimed its own accuracy without independent testing. A cognitive faculty cannot bootstrap itself into legitimacy. Its reliability must be demonstrated externally.

Challenge:
If the deliverances of the faculty are confined to metaphysical or supernatural domains (e.g., the nature of the afterlife), they cannot be externally verified, and the regress cannot be halted. In such cases, confidence in the faculty becomes a leap of faith rather than a justified belief.

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4. Avoiding Ontological Smuggling

One of the most subtle but pervasive epistemic errors occurs when subjective certainty is illegitimately converted into objective existence claims—assuming that because one feels that God exists, God therefore does exist. This is an unjustified leap from internal conviction to metaphysical assertion.

Testing Method:
Beliefs about the existence of God or divine action must be corroborated with external arguments and evidence—cosmological reasoning, archaeological records, historical documentation, or logical coherence. The mere output of a faculty, no matter how confidently expressed, does not entitle one to assert the existence of its supposed object without further support.

Philosophical Justification:
A poker player may feel certain that an ace is in the deck, but unless the card is revealed, the claim remains unsubstantiated. A rational epistemology demands a strict boundary between “I believe” and “it exists.” This boundary must be crossed only by publicly accessible evidence.

Challenge:
Religious traditions often blur this distinction, treating strong inner conviction as sufficient grounds for existence claims. Without additional evidence, such beliefs remain ontologically speculative and epistemically vulnerable.

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5. Eliminating Logical Fallacies and Epistemic Weaknesses

If the defense of the sensus divinitatis relies on faulty reasoning, its epistemic foundation collapses. To be credible, it must avoid fallacies like begging the question, special pleading, and false analogy.

Testing Method:
Evaluate the faculty alongside other discredited or unverified faculties (e.g., ESP, clairvoyance) and demonstrate superior reliability. Additionally, it must meet the same standards applied to perception, memory, and reasoning. Finally, defenses must avoid relying on theological authorities or intuitions without independent justification.

Philosophical Justification:
Claiming a special exemption for the sensus divinitatis—declaring it reliable without meeting the burden of proof—is indistinguishable from accepting magic or superstition. Epistemic trust cannot be extended merely because a belief is longstanding, widespread, or deeply felt.

Challenge:
Most justifications of the sensus divinitatis fail to demonstrate why it should be treated differently from other unreliable intuitions. Without strong evidence, its claims remain logically and empirically suspect.

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Conclusion

For the sensus divinitatis to be treated as a credible cognitive faculty, it must:

✓ Demonstrate reliable and verifiable outcomes
✓ Be bounded by objective criteria that distinguish legitimate outputs from subjective noise
✓ Resolve the regress of justification without presupposing its own validity
✓ Avoid conflating belief with existence by supplying external evidence for ontological claims
✓ Uphold logical consistency and avoid fallacious reasoning

Until these epistemic standards are met, the sensus divinitatis cannot be considered a justified or trustworthy basis for belief in God or divine revelation. It remains, at best, a psychological phenomenon in need of further investigation—not a reliable faculty warranting theological conclusions.

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Properly Basic Beliefs and the Incompatibility with Bayesian Epistemology

Alvin Plantinga’s concept of properly basic beliefs, particularly as applied to belief in God via the sensus divinitatis, attempts to exempt certain beliefs from evidential scrutiny. While this notion was crafted to shield religious belief from the demand for inferential justification, it rests upon assumptions that sharply diverge from the principles of Bayesian epistemology. When examined carefully, the properly basic belief model proves epistemically incoherent within any probabilistic or gradient-based framework. This essay argues that the properly basic label operates on an inappropriate binary model of belief and justification, rendering it incompatible with the defeasibility and gradational updating inherent in Bayesian reasoning.

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1. The Bayesian Gradient and the Incompatibility of Epistemic Thresholds

Bayesian epistemology models belief as credence, or a degree of confidence in a proposition, quantified between 0 and 1. Belief, under this model, is never binary. Even perceptual beliefs with high reliability, such as “I see a tree,” are not treated as incorrigible; rather, they are granted a high prior probability based on past calibration but remain open to revision. That openness is essential: a belief is rational to the degree that it is proportioned to the available evidence and is updated accordingly when new evidence arises.

Plantinga’s notion of properly basic beliefs resists this gradient entirely. In his model, once a belief is classified as “properly basic,” it is deemed epistemically justified without inference or evidence. This signals an epistemic threshold—a binary condition in which justification is “on” or “off,” not continually variable. The belief either qualifies as basic (and thus justified) or it does not, leaving no room for degrees of justification. Such binarism conflicts with the core Bayesian insight that belief is inherently defeasible and continuously revisable in light of new data.

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2. The Illegitimacy of Epistemic Immunity in a Probabilistic Framework

Plantinga’s approach attempts to render certain beliefs immune to defeat by classifying them as properly basic. However, Bayesian epistemology disallows such immunity. No belief, regardless of origin or intuitive strength, is excused from the demand for evidence. Instead, Bayesian models use prior probabilities derived from reliability and historical calibration, and update credences via Bayes’ Theorem as new evidence becomes available. Even our most intuitive beliefs are assigned a high prior—not an epistemic blank check.

If belief in God were modeled Bayesianly, one could assign a high or low prior depending on the reliability of the mechanisms purported to justify it—such as the sensus divinitatis. But that reliability itself would be subject to empirical and probabilistic scrutiny. The very act of removing such a belief from the evidential playing field, as Plantinga attempts, constitutes epistemic special pleading. A belief cannot be both defeasible in principle and immune to probabilistic revision in practice.

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3. The Problem of Reifying Justification into Ontological Privilege

A related epistemic error in the properly basic framework is the reification of epistemology into ontology. Plantinga treats belief in God, once granted properly basic status, as if it reflects an actual divine reality—based on the assumed existence of a God who endows humans with a sensus divinitatis. But this violates a basic principle of Bayesian reasoning: credences are measures of belief, not assertions of fact. The high probability of a proposition does not collapse into certainty or ontological truth. The conflation of internal conviction with external reality is a category mistake, particularly dangerous when it comes to metaphysical claims that lack intersubjective verification.

In Bayesian terms, the rationality of belief is indexed to how well it tracks with observable outcomes, not to how forcefully or immediately it presents itself in consciousness. Plantinga’s model erases that distinction, creating a theological feedback loop in which the very belief in God is used to justify the mechanism that allegedly detects God’s existence. This circularity would fail under any probabilistic scrutiny.

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4. Bayesianism Requires Uniformity of Epistemic Accountability

One of the strengths of Bayesian epistemology is its uniform demand for evidence across all domains of belief. Whether dealing with memory, perception, scientific inference, or metaphysical speculation, the standard remains: assign a prior, gather evidence, and update accordingly. Plantinga’s framework violates this uniformity by assigning a separate epistemic status to certain religious beliefs. This bifurcation is not just unjustified—it is methodologically incoherent. To allow some beliefs to escape evidential constraint while demanding it of others introduces epistemic double standards.

A Bayesian agent cannot, without contradiction, endorse two incompatible standards of justification: one probabilistic and evidence-sensitive, the other foundational and exempt. Any such exemption, if allowed, opens the door to arbitrary belief adoption, thereby undercutting the very concept of rationality.

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Conclusion

Plantinga’s model of properly basic beliefs cannot be reconciled with Bayesian epistemology. The notion rests on a binary threshold model of belief that is fundamentally incompatible with the gradient, revisable, and probabilistic nature of rational credence. It grants unjustified immunity to certain beliefs, violates the principle of uniform evidential accountability, and reifies internal conviction into metaphysical assertion without evidential support. In contrast, Bayesian reasoning treats all beliefs—even those grounded in perception or intuition—as defeasible and subject to revision in light of evidence. Any belief that resists this framework is, by definition, epistemically suspect. If we are to preserve coherence, consistency, and intellectual integrity in our epistemology, we must reject the category of properly basic beliefs as both conceptually confused and epistemically obsolete.

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