➘ #08 Source Article
Fitch-Style Natural Deduction Proof (Core Argument)
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Annotation: If
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Proof
Annotation: If the appeal to
Annotation: Cross-religious ubiquity is observed (Muslim salat, Hindu meditation, Buddhist practice). Empirical premise from the paper’s comparative section.
Annotation: If ubiquity holds, then- From 2,3:
Annotation: Modus ponens on 2 and 3 yields failure of specificity.
Annotation: The paper argues private, first-person experiences lack intersubjective adjudication; no public calibration analogous to perception/memory.
Annotation: Defenses that privilege the inner witness over counter-evidence (e.g., proper basicality, “witness has priority”) render justification circular.- From 4,5,6:
Annotation: Conjunction fails because at least one conjunct ( - From 1 by contraposition:
Annotation: If the criteria block fails, reliability cannot obtain. This is the logically equivalent contrapositive of line 1. - From 7,8:
Annotation: Modus ponens on 7 and 8 gives that
Annotation: If- From 9,10:
Annotation: Modus tollens: since - Optional strengthening with deception:
Annotation: If
Annotation: The inner witness cannot rationally serve as a discriminator between true and false claims about Christianity. Conclusion of the proof.
Corollary: Likelihood/Bayesian Update
Annotation: Competing explanations of
Annotation: The data are more expected if psychology/culture/deception explain
Annotation: The Bayes factor favors
Annotation: Upon updating on
Annotation: Both the categorical proof (
◉ A plain English explanation of the symbolic logic above.
The central question is whether the “inner witness of the Holy Spirit” can actually serve as reliable evidence that Christianity is true. To test this, the paper sets out criteria: if such inner confirmation is to be trusted, it must be specific to Christianity, it must be testable in a way that others can check, and it must avoid circular reasoning.
First, when we look across religions, we see that Christians are not the only ones who report feelings of divine assurance. Muslims, Hindus, Buddhists, and others describe similar experiences during their prayers and rituals. Because of this cross-religious ubiquity, the experience is not specific to Christianity. It shows up everywhere, so it cannot be used to uniquely mark Christianity as true.
Second, these experiences are inherently private. They cannot be checked by outside observers the way that memory or sense perception can be tested. This means they fail the criterion of testability. There’s no independent method to confirm or falsify a person’s report of feeling the Spirit’s witness.
Third, attempts to defend the inner witness often end up being circular. For example, the claim that “the Spirit assures me that the Spirit is trustworthy” assumes what it is supposed to prove. This sort of reasoning doesn’t provide an independent justification, so it fails the criterion of non-circularity.
Taken together, these failures mean the inner witness is not reliable. And if it isn’t reliable, it cannot function as discriminative evidence for Christianity. That conclusion follows logically: a piece of evidence cannot confirm a claim unless it actually tracks truth in a consistent, exclusive, and testable way.
The argument is strengthened further when Christian theology itself admits that deceptive spirits could mimic the experience. If Satan or false spirits can produce the same feelings of peace or assurance, then the experience underdetermines its source—it could be genuine or deceptive, with no way to tell. That makes the witness even less trustworthy.
Finally, when the evidence is reframed in terms of probability, the conclusion is the same. If the inner witness were truly divine, we would expect these experiences to be unique to Christians and resistant to psychological explanation. But in reality, they are widespread across religions, highly dependent on psychological and cultural triggers, and even acknowledged as potentially deceptive. This makes the evidence much more likely on a naturalistic hypothesis (psychology, culture, or deception) than on the divine-witness hypothesis. In Bayesian terms, the likelihood ratio favors the naturalistic explanation, which means the divine explanation loses credibility once the data are considered.
In short, the symbolic proof shows that inner confirmation experiences fail every major reliability test: they are not unique to Christianity, not independently testable, and defended only through circular reasoning. Because of this, they cannot function as genuine evidence for Christian truth. When the same reasoning is expressed in probability terms, the conclusion is reinforced: the data make far more sense if explained by human psychology or the possibility of deception than by divine confirmation.
Free of Faith 
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