There are a lot of good arguments for theism / against atheism (like the argument from contingency). There are also some good ones which unfortunately have been misused so often that they have been identified as bad ones (like Pascal’s Wager). Even more unfortunately, there are also some genuinely bad ones (like the argument from the banana), and some of these are quite popular.
One of the worst is all the more dangerous because it sounds enough like a good argument that it is often made by seasoned apologists. I don’t think it has a name, but the idea is that in order for someone to know that there is no God, one would have to have to be God. Even the more “sophisticated” versions of this schoolyard argument are fallacious, and this needs to be called out before the argument does any more damage.
Proving Universal Negatives
It is popular in apologetic circles to argue that one cannot prove a “universal negative” (aka a “negative existential proposition”) such as “God does not exist.” This has some intuitive appeal – after all, how can one make an assertion concerning all of reality (i.e., “God does not exist anywhere.”) without knowing all of reality? Indeed, the famous atheist philosopher Bertrand Russell once admitted that when it comes to the existence of God, the proper “attitude may be that which a careful philosopher would have towards the gods of ancient Greece. If I were asked to prove that Zeus and Poseidon and Hera and the rest of the Olympians do not exist, I should be at a loss to find conclusive arguments.” However, the argument still fails as an apologetic strategy.
The underlying mistake is that the problem of proving a universal negative only applies to things that (at least) can possibly exist. So, for example, it might be impossible to completely disprove the existence of unicorns, simply because of the difficulty of searching out every possible location such creature might inhabit (perhaps extending to other planets). Thus, it would be extraordinarily difficult to definitively prove that “there are no unicorns in existence anywhere.”
When it comes to the existence of Santa Claus, however, it would not be nearly as difficult. This is because the existence of a being answering to the standard description of Santa Claus can be shown to be definitively impossible. Rather than surveying all possible locations where such a being might be found, one can simply note that the conditions required for such a being to exist are essentially impossible.
Put another way, while I may not be able to prove the non-existence of any 10′ tall bachelors, I can certainly prove the non-existence of married bachelors. In a similar fashion, if one could show that based on the type of being that God would be if he existed that such a being was impossible, then the universal nonexistence of God could be known without “knowing it all.”
Requiring Godlike Powers
A corollary to the above mistake is the followup conclusion that one would need to be godlike oneself in order to coherently deny God’s existence. The idea is that one would have to be omniscient and / or omnipresent (know everything there is to know or be everywhere there is to be) in order to posses the knowledge that God does not exist, because anything less would leave the door open for God’s existence in a heretofore unknown part of reality. But omniscience and omnipresence are attributes of deity. Thus the popular conclusion is that in order to disprove God, one would have to be God.
This is a popular but philosophically ill-informed apologetic tactic. For example, seminary president and popular apologist Alex Mcfarland writes,
“It is important to realize something about being an atheist that even most atheists fail to acknowledge and that is that atheism requires omniscience (complete knowledge of everything).… An atheist is making a positive assertion that there is no God. The only way that anyone could make such an assertion would be to presume that he knew everything about everything.” (“The 10 Most Common Objections to Christianity”, 37-38).
The same claim is made by the president and founder of Christian Apologetics and Research Ministry (the top Evangelical apologetics website) Matt Slick:
Then you cannot KNOW there is no God. . . . atheism is illogical. You cannot know there is no God. To do that, you’d have to know All things to know there is no God. (“An Atheist Says He Knows There Is No God”)
This argument is also made by Christian research institute president Hank Hanegraaff:
“Atheism involves a logical fallacy known as a universal negative. Simply stated, a person would have to be omniscient and omnipresent to be able to say ‘there is no God’ from his own pool of knowledge. Only someone capable of being in all places at the same time — with a perfect knowledge of all that is in the universe — can make such a statement based on the facts. In other words, a person would have to be God to say there is no God. Hence, the assertion is logically indefensible. By using arguments like this, you will often find that an atheist quickly converts to agnosticism and is thus making progress rapidly in the right direction.” (“The Folly of Denying God” CRJ, 1990)
The argument does not seem to be losing any steam, either. As late as 2013, Ravi Zacharias made a similar claim on his Facebook page:
These alleged requirements are really just another species of the previously-discussed problem of proving a universal negative. Only empirical inductive arguments that require as their support the totality of reality (a “perfect induction” on a universal scale) would fall into such a trap. Rational deductive arguments (especially those involving direct contradictions) do not suffer from this flaw. (Interestingly, given the generally poor reception of the only purely deductive argument for the existence of God – Anselm’s Ontological Argument – among theists and atheists alike, it may be the case that atheists actually have the upper hand in attempting to argue their position based on logic alone.)
This particular argument fails due to the basic difference between empirical-inductive and rational-deductive proofs for a universal conclusion. Because inductive arguments are (by definition) those which (usually) give only probable support to their conclusion, and are usually based on empirical facts for their support, the idea that one could use such a method to disprove God is clearly problematic. There are, however, purely rational deductive arguments which would (in theory) definitively prove their conclusion by demonstrating that the notion of God is self-contradictory. And, since these kinds of arguments are indeed given against the existence of God, then it is not the case that “atheism is logically indefensible” (at least on these grounds). Thus, it is also false that atheists would have to posses godlike powers to know that God does not exist, because contradictions can be proven with merely human abilities.
Although not a lot of atheists have spoken out against this specious argument, it is a very bad one and makes theists look bad. Please do not use this argument, and alert those who have to its failure. For a better exposition of this kind of argument, see Peter Kreeft’s: