Circular reasoning is a type of logical fallacy where the premise is used to prove the conclusion. A basis example would be:

  1. This historical movie is creditable.
  2. Why?
  3. Because it says so.

In this example, someone is assuming a movie is creditable because because it says so. Yet to believe its words are true, one would have to believe it is creditable. This is a classic example of circular reasoning or begging the question.

I've accepted this idea of circular reasoning for quite some time, until someone used it in terms of logic. According to them, logic is sound, because it is logical. At first glance, this statement is circular, making it fallible. Yet one must admit, it is a hard argument to refute. In the same way, this person went on to say that to define every word in the dictionary one would have to use other words in the dictionary, making the definitions circular. Once again, this seems reasonable.

They then went on the draw the connection between this circular reasoning in logic and their belief in the Bible. They said that despite the fact the Bible can be supported as valid through historical research and eye witness testimony, it can also be supported by this circular argument.

My question is two-fold. Can circular reasoning be logical, like in the case of logic itself? If so, could it be applied to the Bible?

  • The Biblia Sacra is a magnum opus in logic.
    – Hudjefa
    Commented Mar 15, 2023 at 2:54
  • 6
    Circular reasoning is logically valid ("logical") because A → A is a logical tautology. It can be applied to the Bible, or to anything else. But it does not support anything it is applied to, i.e. does not add any credibility to it. Whether it is logically sound depends on whether A is true. Since A → A tells us nothing about that it is worthless as an argument for A. For this reason, circular reasoning is considered an informal fallacy, despite being logically valid, and sometimes even sound. An argument does not need to be "illogical" to be worthless.
    – Conifold
    Commented Mar 15, 2023 at 3:36
  • @Conifold, have you applied for police protection? 🙂
    – Hudjefa
    Commented Mar 15, 2023 at 7:37
  • Circular reasoning is the same as fiating an axiom outright, since the chain of logic adds nothing. Fiating an axiom can't be said to be right or wrong, it just is what it is. What it doesn't do is establish the axiom as an absolute truth, which is also the case for circular reasoning.
    – H Huang
    Commented Mar 15, 2023 at 8:05
  • +1 For teaching me creditable is a synonym for credible.
    – J D
    Commented Mar 15, 2023 at 21:37

6 Answers 6


Your movie example is missing two unstated premises.

There exists some incentive for honesty in statements made by a film about whether it is creditable.

This film is produced by people who respond to incentive structures of that kind, and who know the difference between truth and falsehood.

Few would believe that a propaganda film about the wise and virtuous character of a totalitarian dictator was creditable: although the people producing the film are likely responsive to such incentives, there exists no incentive structure promoting honesty on this subject.

Few would believe that a home-made movie narrated by the ravings of an obviously deranged drug addict was creditable: although there may be incentives for honesty, this kind of person cannot be expected to respond to such incentives, and may not know the difference between truth and falsehood.


Can circular reasoning be logical, and can it provide support for the Bible?

Well, no. Here is your example:

  1. This historical movie is creditable.
  2. This historical movie says that it is creditable.
  3. Thus, this historical movie is creditable.

The problem here is that the middle term (creditable) is not distributed in either premise. Thus, each statement can be true independently, but there is no idea (middle term) which links the two to form a larger truth (that the movie is creditable).

  • +1 To the point!
    – J D
    Commented Mar 15, 2023 at 21:35

Your question is a classic theme in epistemology, which is the topic about the circularity in reasoning also known as epistemic circularity (IEP):

An epistemically circular argument defends the reliability of a source of belief by relying on premises that are themselves based on the source. It is a widely shared intuition that there is something wrong with epistemically circular arguments.

Thus, many people reject that God is real because the Bible says so, because when asked how a person of faith knows the Bible is true, the adherent to the Bible merely claims that God or the Holy Spirit reveals to them. We say such a person believes in epistemic revelation. In regards to logic, how do we know logic is good and true falls to the philosophy of logic. The intuition is that circularity in definition or justification is suspect, but there are many contexts that make it clear that SOME circularity is not only acceptable, but desirable. Propositions often contain impredicativity. In terms of epistemic circularity, it persists in too many thinkers' mind not to offer some pragmatic benefit. Ultimately, the question may revolve around belief revision. If one starts off believing the Bible, and then builds a world view that affirms the Bible, then one has a consistent worldview. Psychologically, such a philosophy would reduce cognitive dissonance. A persons material logic supports belief in the Bible, and the Bible supports belief in the person's material logic. One's formal logic will even grow to conform to one's beliefs.

My question is two-fold. Can circular reasoning be logical, like in the case of logic itself? If so, could it be applied to the Bible?

So, yes, logical systems and informal logic can indeed be circular and defensible if one finds other ways to ground meaning and truth, such as appeals to faith or embodied cognition as a basis for imbuing logic structure. And yes, it absolutely can and is applied to the Bible by theologians regularly. In fact, atheists who use logic to deny the supernatural and theologians who affirm it both, in a way, are invoking a certain degree of circularity in their epistemic arguments simply because words don't have meaning independent of experience. Each side merely appeals to their experience as a foundation for justifying the degree of circularity in their own worldview.

If your question is 'Should they'? Then you are now entering the territory of wrestling with Agrippa's tropes:

Dissent – The uncertainty demonstrated by the differences of opinions among philosophers and people in general.
Progress ad infinitum – All proof rests on matters themselves in need of proof, and so on to infinity, i.e, the regress argument.
Relation – All things are changed as their relations become changed, or, as we look upon them from different points of view.
Assumption – The truth asserted is based on an unsupported assumption.
Circularity – The truth asserted involves a circularity of proofs. [emphasis mine]

In real human beings, there is a tendency to create worldviews that exhibit arguments from a mixture of these tropes. Just how and when one should do each seems to be just as much a question of psychology as logic proper, and the decisions about how and when is a question of axiology. A metaphilosopher recognizes that the plurality of philosophical positions is itself worthy of study, and that modern science seems to suggest that there are biological factors in our beliefs such as the biology of political views. Thus, if you're looking for a one-right answer to your question, you might be dismayed to find that there isn't a canonical response. Many highly intelligent thinkers diverge on such specific questions.


If we view circular logic from the standpoint of digital logic in a computer science context, the circuit model of a circular argument is a straight piece of wire.

You always and forever get out of it exactly what you feed into it (i.e., 1 in yields 1 out, 0 in yields 0 out) but it performs no operation.

In a programming context, this is called a NOP (for no operation) which means it can be deleted from any string of instructions with no consequence.


Although on a bare enough logical level, there isn't a direct problem with circular inferences (see Conifold's comment about A implying A), what if we frame the problem on the level of epistemic logic? So to say:

Aaron was talking to Zoe about two-headed giraffes living underground in Siberia. She said, "I don't know that there are two-headed giraffes there, or anywhere." Aaron replied that according to the Principle of Polycephalous Animals, there must be two-headed samples of any animal, at some point, somewhere, anywhere, so even if not true now, it either was true before or would be true one day that there were such giraffes in such a location as he claimed. "So I do know that," he said. Did Zoe have a reason, modulo epistemic logic, to infer that now she too knew the truth about those giraffes?

It seems as if these kinds of circular arguments in epistemic logic miss the point of unresolved questions in the first place. One does not find that one knows the specific answers to such questions just by thinking that one knows them, much less does one provide others with reasons to believe that they know these things thereby the by.

So then:

Adam was talking to Zendaya about the Bible, claiming that it was from God. "I don't know that God exists, though," she said. "The Bible says He does, so there's that," Adam continued. How can Adam's reasoning be compelling (or even persuasive!) for Zendaya, if she has not entered into the circle that Adam has entered into? Has Adam admitted the possibility (and extreme probability) of other explanations for the Bible's origins?

When circular reasoning seems justified, it is usually with respect to close-to-trivial assertions, or abstractions that are hard to get at directly anyway. In the latter case, the object of one's assertions might not even be itself circular so much as perceived partwise, by us, in a circular manner: the parts are simultaneous but our consciousness of them has to run a circuit across the structure in order for us to see how they fit together. The existence of God, and an apparent decision of God's to endorse a certain book (or, in the Christian limit, a certain translation of a certain version of a certain book), are not trivial and not so abstract matters, so it would be surprising to find that God had made our means of knowing Him depend on performing an esoteric exercise in the juggling of pious obscurities.

On the other hand, in the Reformed epistemology school, they've made a whole cottage industry out of this kind of thinking: they call it "presuppositional apologetics".

  • +1 "It seems as if these kinds of circular arguments in epistemic logic miss the point of unresolved questions in the first place. " That's a feature, not a bug! :D
    – J D
    Commented Mar 15, 2023 at 22:40
  • 1
    @JD I can't deny self-answering questions altogether (my own belief system depends on a specific self-answering question, after all). And there are looped arguments in theology that can have merit. I would think that if Zendaya had to argue with a Christian and a Muslim at the same time, not only would they resort to non-circular (but deformed) arguments to try to one-up each other, but I think Zendaya would have even more reason to distance herself from her interlocutors in that she'd see that even if Adam's argument was OK, it would lead to accepting the Bible and the Quran. Commented Mar 15, 2023 at 22:51
  • I think the acceptance of epistemic circularity is a preliminary means at arriving at confidence in principles. In the case of competing claims by Christianity and Islam, while each in isolation could be seen as reliabilist or evidential epistemic justification, the circularity itself underdetermines the conclusion that one or other specific epistemic justification is sufficient. Both Adam and Abdullah can agree that Zendaya should embrace epistemic circularity as evidence of God's existence, but the moment they disagree about the specific, respective epistemic arguments, Zendaya has grounds..
    – J D
    Commented Mar 15, 2023 at 23:22
  • 1
    Now that I think about it, Zendaya can go a step further and say from an evidentialist interpretation of epistemology, "the fact that you both, Adam and Abduallah, can only agree that 'God exists' and disagree on 'what God is' is evidence that God's existence is not self-evident. Thus, it seems as a doubter that not only are circular epistemological claims impoverished for and establishing the existence and nature of God, but they are evidence of a fundamental defect in theological reasoning." As long as she admits her stance is fallibilistic, A&A now have to defend theological epistemology...
    – J D
    Commented Mar 15, 2023 at 23:33
  • 1
    as an enterprise since it doesn't seem to concede a spot to the skeptic at the table and seems not to admit justifications of disbelief on its face in a world of apparent prima facie causes of doubt such as illusion, cognitive bias, deceptions, and confabulation.
    – J D
    Commented Mar 15, 2023 at 23:33

As is evidenced by the persuasiveness, proliferation and popularity of religious apologists, including many who are academically trained, reasoning of all sorts - whether sound or not - can be employed to successfully engender support for texts containing claims which - when subject to analysis - fall short of the standards of evidence that we've so heavily relied upon in order to progress as far as we have.

As user Conifold points out, circular reasoning is logically valid, but useless, other than when it used to persuade people unfamiliar with why it is problematic, and who are unable to recognise circular reasoning (and other fallacies) when it arises.

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