All too often, I hear theists claim that atheism is a belief, as if to imply that it requires the same leap of faith that theism does. The flaw in their argument is that “belief” has multiple meanings, and conclusions drawn about “beliefs” based on that word’s use alone tend to reveal more about semantics than about cognition.

The word "believe" can be affixed to all kinds of propositions, some rational, some not. It does not follow that someone using the word "belief" is necessarily engaging in an irrational process any more than it follows that someone using the word "know" is necessarily making a factual assertion. After all, “I believe” can be used not only as a declaration of faith (“I believe in God”), but also as a declaration of dedication to a principle (“I believe in freedom”), an educated guess (“I believe Joe went to lunch with Susan), an expression of shock or incredulity (“I can’t believe he did that!”), a judgment passed on the veracity of a statement (“I don’t believe a word of his story”), or simply for emphasis (“I believe you’ve got some explaining to do!”). We can tag the words “believe” or “know” in front of anything without changing the underlying nature of the proposition.

Hence, claiming to “believe” that 10 X 10 = 100 is no less rational than claiming to “know” that 10 X 10 = 100. Regardless of whether we “believe” it or “know” it, it is an easily verified statement of mathematical truth. Likewise, “knowing” that invisible pink unicorns exist is no more rational than “believing” they exist, because there’s no verifiable evidence that they do. To determine if a belief or assertion is rational without semantics getting in the way, we must therefore remove the words “believe” or “know” and analyze the validity of the proposition itself. Then, depending on the type of proposition, different types of evidence must be proffered, as follows:

Opinions are subjective propositions; therefore, verification doesn't apply:
-My neighbor Bob is a lunatic.
-That was a boring, predictable movie.
-I'm hungry.

Extraordinary Claims are theoretically verifiable claims that exceed normal human experience and often supersede the laws of nature; they require extraordinary evidence:
-An alien abducted me last night.
-An ancient sea monster lives in Loch Ness.
-God, the omnipotent, omniscient creator of the universe, exists.

Mundane Claims are readily verifiable claims regarding an incident or situation that falls in the range of normal human experience; they require reasonable evidence, often of an inductive nature:
-Don ate lunch at his Mother’s house yesterday.
-The Eiffel Tower is in Paris.
-Ducks lay eggs.

Scientific Theories are complex explanations of natural phenomena; they must be proved through extensive scientific research and inductive reasoning, and are subject to peer review:
-The Earth rotates around the Sun in an elliptical orbit.
-Objects thrown into the air will fall to Earth again due to the force of gravity.
-Men and apes have descended from a common ancestor.

Mathematical Truths are statements regarding mathematical concepts established using deductive reasoning:
-A triangle has three sides.
-The circumference of a circle is 2πr.
-The square root of 400 is 20.


The rational stance towards mundane claims is to keep an open mind without disregarding prior experience with or knowledge of the subject. But the rational stance towards extraordinary claims, and especially those superseding the laws of nature, is one of skepticism. Since extraordinary claims can run the gamut from mildly speculative to wildly imaginative, we are right to presume that invisible pink unicorns, as well as ghosts, ghouls, giants, and gods, do not exist unless and until sufficient evidence has disproved all possible natural explanations (including hoaxes, exaggerations, and fantasies) in favor of a single remaining supernatural one.

Even then, there's a difference between initial skepticism and informed skepticism. Atheists begin from a position of skepticism regarding supernatural claims in general, but we also evaluate and reject a great deal of purported evidence before finally arriving at the conclusion that God, as defined by any number of religions, does not exist. Therefore, atheism is a position of informed skepticism. The Christian attitude towards Thor and the Buddhist attitude towards Zeus involve informed skepticism, too. Atheists just take the rational process one step further.

Is it close-minded not to seriously entertain the idea of fairies who only appear to those who believe in them, teapots orbiting on the other side of the sun, a Flying Spaghetti Monster with noodly appendages, a celestial tortoise who carries the universe on his back, or any number of other unverified or unimagined entities? How can we be absolutely sure these things don't exist if we approach them with such skepticism?

The answer is simple: the rational approach to extraordinary claims is to start from skepticism and to adopt a stance of assertion or acceptance only if extraordinary proof has been provided. A predisposition to serious consideration of all fanciful metaphysical assertions is not open-mindedness; it’s superstitious gullibility. Clearly, then, atheism is not an irrational belief and does not require a leap of faith. Atheism is the rational position we arrive at when we apply the principles of informed skepticism.