The struggle to definitively prove or disprove the existence of atheists has puzzled philosophers for centuries. Some have proposed the cosmological argument — “many cosmologists seem to be atheists” — while others have fallen back on the argument from design — “without atheists, who would believers have to argue against?”
But the Catholic Encyclopedia seems unconvinced by these arguments:
The most trenchant form which atheism could take would be the positive and dogmatic denial existence of any spiritual and extra-mundane First Cause. This is sometimes known as dogmatic, or positive theoretic, atheism; though it may be doubted whether such a system has ever been, or could ever possibly be seriously maintained. Certainly Bacon and Dr. Arnold voice the common judgment of thinking men when they express a doubt as to the existence of an atheist belonging to such a school. Still, there are certain advanced phases of materialistic philosophy that, perhaps, should rightly be included under this head. Materialism, which professes to find in matter its own cause and explanation, may go farther, and positively exclude the existence of any spiritual cause. That such a dogmatic assertion is both unreasonable and illogical needs no demonstration, for it is an inference not warranted by the facts nor justified by the laws of thought.
You have to admire the confidence — the fact that “dogmatic atheism” is “both unreasonable and illogical needs no demonstration,” and let’s leave it at that. It’s a little bit different from the tack they take in another entry:
Formal dogmatic Atheism is self-refuting, and has never de facto won the reasoned assent of any considerable number of men.
The Encyclopedia does not dirty its hands by explaining the nature of this self-refutation, any more than it explained the previously-noted unreasonability and illogic. I like it! It’s kind of like arguing on the internet.