One common reason I hear for atheism is the claim that there is no proof that God exists. Several questions can be asked about this objection. What exactly does the objector mean by proof? If all things need to be proved to be sensibly believed then what is the proof that all things require proof? Further, what is the proof for the claim that there is no proof? Finally, if some things can be believed without proof, why is God in the “must be proved” category?

There is however another question. If the absence of proof for a thesis provides rational grounds for claiming the thesis is false then wouldn’t absence of proof for atheism provide grounds for claiming that atheism is false? The person who is an atheist on the basis of this objection seems, on the face of it, to work with a double standard here. He claims that theism requires proof and that the absence of such proof requires us to reject theism as false. However, he thinks that atheism can be believed in the absence of proof for it.

What is the basis for this distinction on the atheist's part? To avoid this prima facie inconsistency the atheist needs to provide some reason why theism requires proof but atheism does not. In the absence of any good reason his position seems simply arbitrary.

This brings me to the issue I want to address. One common reason, one I often hear expounded is that theism asserts a positive claim, it affirms the existence of something. Atheism, however, makes a negative claim, it denies the existence of something. According to the line of argument I want to address negative statements cannot by their nature be proven. The objector argues that it is impossible to prove a universal negative; however, positive claims can be proven. Hence, for this reason, positive claims need to be proved and negative ones do not. We can assume the denial of somethings existence in the absence of proof but we cannot affirm the existence of something without proof.

I have heard this claim repeated in cyber space over and over. I think it’s a very bad argument for three reasons.

First, the claim that “you cannot prove a negative” is false. Here are some examples of negatives which can be proved:

a) there is no 1,000,000 mile high pile of African elephants in New Zealand
b) there are no promiscuous virgins
c) there are no married bachelors
d) there is no planet between earth and the mars
e) there is no such thing as a square triangle

One can prove a negative statement in several ways. One can show that an existential statement would, if true, entail a contradiction or metaphysical absurdity or the denial of things which we know are the case.

Second, if one claims that positive existential statements always need to be proved, one is lead into a fairly radical skepticism about everything. Take the claim that there exists a physical world independent of my senses. Or that other people (with thoughts and feelings) exist. Or that there exists a world that is more than six seconds old. There are well known problems with being able to prove these things and yet each one is a positive existential statement. On the view sketched above we are committed to denying these things exist.

In fact I think a little reflection shows that it would, on the assumption that positive existential always need to be proved, be almost impossible to prove everything. If I prove the existence of something I do so by appealing to other premises which assert facts. But facts are things that exist in the world. Consequently, I would need to prove these facts exist before I can appeal to them but I can't prove these facst unless I appeal to them as proof.

It follows that if I cannot prove anything, and one should deny the existence of whatever cannot be proven, then the only option is to deny the existence of everything.

Let me turn to my third reason for thinking this line of argument is flawed. Suppose one grants [a] that it is impossible to prove negatives; and also that for this reason, [b] one should deny a positive existential statement unless proof is provided. Both [a] and [b] create problems for an atheist. Consider the following claim, there exist some material objects that were not created by God. This claim is a positive existential statement. Hence, until the atheist can provide proof that it is true, until he can prove that some material objects were not created by God, he must deny that such objects exist. However to deny this statement is to affirm that every material object was created by God and hence that God exists.

In conclusion, the claim that theists bear the burden of proof because they are making a positive claim and that the denial of positive claims is the default position until proven is a problematic claim.

Matt