This is asserted as logic. "a person .." is false to someone X so "that someone X is an atheist" is true. Modus ponens, if-then. If (NOT (Believes (X, (God = Person))) then (NOT (Believes, (X, God))). I would assert that many people believe in God but do not believe God is a person, and so they remain theists by their own attestation. One example from the 1600s is Rene Descartes, but there are many who believe there is a God but it is impossible he is a person. Descartes, for example, asserts he believes in God but God cannot deceive (i.e., lie). And he asserts therefore that God cannot be a person because no person cannot lie (deceive).

As a logic (Logos) argument, Cain’s statement is a lie. It may be a belief this author holds but this author is evidently lying to a lot of people. Descartes would certainly be one. Descartes' writings are widely regarded as the beginning of the Age of Enlightenment, the Age of Reason, and, notably, the Reformation.

Since God is a word concept which can refer to different things for different people, evidence arguments about God may appear to one person to be true and another person to be false, or an untruthful deceit. "Person" is a word concept which is tautologous since "Person is a Person" is true except in a context where it is asserted to be false as in saying "It is false in my world that a Person is a person". Any sentence can be a lie, any sentence can be true. That is self-evidently true.

It is said that near death, Descartes was asked what is truth, and he sadly responded he still did not know except for deductive truth (e.g., if-then), since no axiom (self-evident truth) can be certain to be true. Deductive truth had been known for a thousand years (e.g., Euclid).

Anyway, making a logos argument about God needs a referent and this article's referent for God has been under dispute for hundreds of years by a lot of people who survived as strongly religious people.

Descartes defines his referent for God and proves that God exists by deduction.

Read him (e.g., "meditations") if you want to read a proof that God exists.

Just say'n.

That said, science provides evidenciary proof by careful observation of referents that anyone can confirm observationally for themselves, and modern science says this about truth and lies..

Which has nothing and everything to do with Religion or Atheism, because both can be true when the referent (in this case "Religion" or "Atheism") has an ill defined referent.

Carnegie Mellon University since 1979 — Cognitive Science, AI, Machine Learning, one of the founding Directors of the Robotics Institute.