What Is Circular Reasoning?

Circular reasoning is a particular misalignment with reason where a person thinks that something is knowable on the basis of a particular kind of assumption: that it proves itself when it truly does not.  Believing that the Bible or Quran is true (in that what it claims about reality is the case) because each book says so is to engage in circular reasoning, reasoning being distinct from reason as will be addressed.  So is believing that one's parents are not lying to you about a given matter because they "would never" do something like that, or that atheism is true because it is "obvious" that there is no god (which is an objective logical falsity [1] and thus could only be assumed, not known).  In each of these cases, there is nothing about the concept itself that has to be true.  The ideas could therefore not prove themselves.

Believing in any of these or other such things on these grounds certainly is to engage in circular reasoning, which is necessarily invalid.  Circularity is not epistemological evidence, much less true logical proof.  What, then, of logical axioms, which on the contrary are absolutely true in themselves and therefore are self-evident because one cannot reject, ignore, or even doubt them without already relying on them (they are self-necessarily true, after all)?  Self-evidence is absolute logical proof, but it only applies to an extremely narrow range of philosophical facts.  For instance, if nothing is true, then this itself is true by logical necessity, and so truth exists regardless of what else is additionally true about reality.  To believe in logical axioms because they cannot be any other way is not fallacious.

Thus, relying on logic to verify the laws of logic is not circular reasoning because logic is inherently true independent of any being's perception or belief or recognition; indeed, it is true independent of all else and is what all other things depend upon.  It cannot be false, and since other things do not have this quality, they are unlike logic.  Logic is not something that either has to be assumed or has to be proven by some prior, more foundational fact.  Even demonstrating to oneself that one's own mind exists--and doubting one's own existence or believing it is an illusion can only be done if one already exists, hence one's own conscious existence also being epistemologically self-evident--still relies on the truth of and one's awareness of logical axioms, of some things following by necessity from others.

Ironically, circular reasoning cannot be invalid unless the laws of logic are inherently true prior to all else and therefore self-evident, or else nothing else could make anything true and there would be nothing erroneous about any philosophical concept or basis for believing it--but even this could not be true without it requiring that logical axioms still have veracity!  Their very falsity could only be the case if they are still true, and therefore their falsity is impossible.  Circular reasoning is an irrational person's fallacious basis for believing any idea they believe proves itself when this is not so.  Reasoning is how people utilize or misuse reason; logic, reason itself, is a set of necessary truths that are all rooted in inviolable axioms of intrinsic veracity.  What makes reasoning erroneous is its deviation from the objective truths of logic, starting with axioms, while logic itself is unaffected by any being.

[1].  https://thechristianrationalist.blogspot.com/2017/04/the-uncaused-cause.html