Not So Fast: There is no Presumption of Atheism

Jason Dulle

Traditionally, atheism has been defined as the belief that no god(s) exists. This is a positive claim to propositional knowledge, and as such it requires rational justification. If there are good reasons to think God does not exist, then the belief that God does not exist is rationally justified. But if there are no good reasons to think God does not exist, then the belief that God does not exist is not rationally justified. The veracity of atheism, then, depends on the atheist's ability to shoulder his burden of proof for the claim that God does not exist.

The practical problem with this definition is that the burden of proof is too great to shoulder. Most of the evidence pre sented against God's existence is not positive, but negative. Atheists typically try to demonstrate why the theist's arguments for God's existence fail or are superfluous, but do not present any positive arguments against God's existence. At the end of the day, even if the atheist is able to defeat all of the theist's arguments for God's existence, all he will have shown is that there are no good arguments for God's existence. He will not have made any headway in demonstrating that God does not exist. William Lane Craig commented on the bankruptcy of this strategy, saying:

I hear all the time that atheism wins by default – in other words, if there aren't any good arguments for God, then atheism automatically wins. So many of these fellows don't offer any arguments for atheism; instead, they just try to shoot down the arguments for theism and say they win by default.  In reality, however, the failure of arguments for God wouldn't do anything to establish that God does not exist. The claim that there is no God is a positive claim to knowledge and therefore requires justification. The failure of arguments for God would leave us, at best, with agnosticism, not atheism.1

This predicament seems to have spawned the desire on the part of some atheists to redefine atheism in a more epistemically-friendly way. Philosopher and former atheist, Antony Flew, redefined atheism, not as a positive belief that god(s) does not exist, but as someone who is simply not a theist: an a-theist.2 On this definition, atheism is not a knowledge claim, but the absence of belief; not a metaphysical claim about the nature of reality, but a psychological claim.

According to Flew, in the absence of evidence for God's existence, one is justified in presuming God does not exist. Rather than providing positive justification for atheism, the presumptive atheist resorts to the supposed lack of justification for theism as proof that atheism is true. The presumptive atheist is not making a positive claim to knowledge, and hence bears no burden of proof to defend God's non-existence with positive evidence. Only the theist bears a burden of proof to establish God's existence. If the theist cannot prove that God exists, atheism is rationally justified by default.

There are several problems with this redefinition of atheism.

Eviscerates Atheism of Ontological Significance

This new definition of atheism as “non-theism,” or a mere “lack of belief in God” transforms atheism from an ontological claim to a mere epistemological claim.  It reduces atheism to an autobiographical note, telling us only about the psychology of its adherent, but nothing about whether God, in fact, exists or not.  As a result, this new definition ceases to be explanatorily meaningful.  Indeed, it ceases to be a view at all.  Babies, and even dogs would qualify as atheists according to this definition.3 That seems patently absurd.  There is a cognitive element to atheism that this new definition does not take into consideration.  If atheism it is to be understood as a meaningful position on the question of God’s existence, it must be about the object, not the subject; ontology, not epistemology. Otherwise, the presumption of atheism is more akin to agnosticism than atheism in any meaningful sense of the word. Indeed, it is difficult to see any meaningful distinction between the two. It appears to be a distinction without a difference.  In the end, agnosticism collapses into agnosticism.

A Positive Claim is Unavoidable

This new definition of atheism seeks to shirk its epistemic responsibility by engaging in meaningless word games. Every negative claim is an affirmative claim in reverse. If I say "I don't believe in Santa Clause" (a negative claim), it reflects my positive affirmation that "I believe Santa Clause does not exist." The same goes for the claim, "I don't believe God exists." The contrapositive of that negative claim is the positive affirmation, "I believe God does not exist." Seeing that every negative claim is a positive claim in reverse, the presumptive atheist cannot avoid making a positive claim, and therefore must shoulder his burden of proof for that claim.

Beliefs and affirmations (epistemology) are intra-mental propositions that have as their object extra-mental realities (ontology)-or at least what we perceive to be extra-mental realities. If I believe grass is green, my belief is not about my belief, but about the real world: that grass is actually green. In other words, beliefs are epistemological affirmations about what we perceive as ontological realities. What then, of the atheist's affirmation, "I do not believe God exists"? As stated, the object of this affirmation is not the world, but about his psychological state. Stated positively, however, "I believe God does not exist" is an affirmation about what is real in the world. Since all negative claims are positive claims in reverse, the presumptive atheist is making an ontological claim, and that claim must be defended. He needs to justify why we should believe the world lacks the presence of a deity.

Absence of Evidence is not Evidence of Absence

The presumptive atheist commits a rational fallacy best represented by the aphorism, "absence of evidence is not evidence of absence."4 As atheist Kai Nielson recognized, even if all proofs for God's existence fail it could still be the case that God exists.5 The only way to rule out God's existence is to present positive evidence against it. This being the case, it does not follow that if the theist cannot present positive evidence for God's existence that one is justified in presuming God does not exist.

"The presumptive atheist assumes that if one has no evidence for God's existence then one is obligated to believe that God does not exist-whether or not one has evidence against God's existence. Atheism, however, is justified only if there is sufficient evidence against God's existence."6 It is an error to conclude that the absence of evidence for God's existence is positive evidence against His existence. One may be epistemically justified in not believing God exists if there is no evidence for His existence, but a lack of evidence for His existence does not rule out the fact that He may indeed exist. That possibility cannot be ruled out until positive evidence against His evidence has surfaced. In the meantime we should remain agnostic on the question.

There are times, however, in which absence of evidence is evidence of absence. This happens when we would expect to find evidence of something's existence, but in fact find none. For example, if Santa Clause exists we would expect to find his home in the North Pole, or have empirical evidence of flying reindeers, elves, or Santa being caught on a security camera while delivering presents inside someone's home. Where evidence should be found, none is found, and thus the absence of evidence is good evidence that Santa Clause does not exist. The principle here is that "the justification conferred...will be proportional to the ratio between the amount of evidence that we do have and the amount of evidence that we should expect if the entity existed. If the ratio is small, then little justification is conferred on the belief that the entity does not exist."7 If the ratio is large, then we are justified in believing the entity does not exist.

This is why it is illegitimate for atheists to compare belief in the existence of God to belief in Santa Clause, arguing that if we accept one as legitimate we have to accept the other. As Paul Copan wrote, "To place belief in Santa Claus or mermaids and belief in God on the same level is mistaken. The issue is not that we have no good evidence for these mythical entities; rather, we have strong evidence that they do not exist. Absence of evidence is not at all the same as evidence of absence, which some atheists fail to see."8

Presumptive Atheists Cannot Escape a Burden of Proof

Presumptive atheist, Michael Scriven, recognizes that justification for a belief is measured by the amount of evidence we should expect to find in its favor compared to the amount of evidence we actually have for it. He argues that we are only justified in believing entity X does not exist if "(1) it is not something that might leave no traces and (2) we have comprehensively surveyed the area where the evidence would be found if the entity existed."9 That being so, atheism is only justified if we have good reason to believe God would have left more evidence of His existence than He did, or if we have comprehensively surveyed every area where evidence might be found if He exists, and found none. This, however, puts a burden of proof on the atheist as well as the theist-the very thing the presumption of atheism hoped to avoid.

Atheism is a Worldview, and Worldviews Require Justification

A worldview is a way of looking at the world; a way of explaining reality, both as it is, and as we experience it. Worldviews make truth-claims about the nature of ultimate reality, and those who make truth-claims shoulder the burden of proof to demonstrate the veracity of those claims. Atheism is a worldview, just like Christianity, Buddhism, and Hinduism. As such, atheists are not exempt from the need to demonstrate the veracity of their worldview. Those who view the world as including a divine being need to justify that worldview; i.e. give reasons why anyone should think that worldview accurately reflects reality. Those who view the world as being void of a divine being need to justify that worldview, and show its explanatory superiority over other worldviews.

The atheistic worldview is not true by default. It must be demonstrated to be true. Neither is a lack of evidence for theistic worldviews de facto evidence in favor of an atheistic worldview. Atheism must stand on its own merits. It must be judged by its internal coherence, explanatory scope, and explanatory superiority over other worldviews. It must be judged by how well it explains reality and human experience. If atheists expect anyone to take their worldview seriously, they need to do more than argue that theistic worldviews lack sufficient warrant. They must show how atheism can explain the existence of the universe, free will, rationality, consciousness, and the like without reference to God. Indeed, they must show that an atheist explanation is superior to, and more likely than other alternatives. If nothing else, then, in the presence of competing worldviews atheists have the burden of proof to show why their worldview is superior to the next. That requires some level of justification for the notion that God does not exist.


Presumptive atheists are often inconsistent. Sometimes they act as if atheism is true by default (due to the supposed absence of evidence for theism) and needs no defense, while at other times they give reasons to reject the existence of God (e.g. the problem of evil). But the presumptive atheist-if he is to be true to his ideology-would not give reasons against God's existence. There is no need to according to presumptive atheism. Atheism is true by default. One does not need any reason to not believe in God other than the absence of any reason to believe in God. At best the presumptive atheist could provide rebutters to the theist's arguments in support of God's existence, but he could not advance arguments against God's existence without tacitly admitting he has a position to defend, and hence a burden of proof. Such an admission would give up the farm! The presumptive atheist cannot claim he has no burden of proof because he has no position to defend, and then proceed to offer arguments in behalf of God's non-existence. Either he does not have a position to defend, or he does. Either he believes evidence is needed, or he does not. If evidence is not needed because atheism is not a position that needs defending, why defend it with supporting evidence? Is it because it bolsters his case? If he has a case, then he has a position, and a position needs to be justified.

Historical Anomaly

If for no other reason, atheists bear a burden of proof because their view has been the minority view for all of recorded history. Why, given the prevalence of theistic beliefs throughout history irrespective of culture, location, or age, should we think God does not exist? A belief that has persisted in various forms for millennia should be given precedence over a contrary belief unless and until evidence for that contrary belief surfaces. If there is no reason to believe god(s) does not exist, then there is no reason to believe atheism is a true description of reality. It is a historical anomaly not grounded in reason.


The makeover of atheism fails miserably. The presumption of atheism is virtually indistinguishable from agnosticism, is rendered meaningless by eviscerating the traditional definition of its cognitive and volitional content, is built on a logical fallacy, cannot avoid making positive truth-claims, and cannot avoid a burden of proof. William Lane Craig sums it up well:

So why, you might wonder, would atheists be anxious to so trivialize their position? …[A] deceptive game is being played by many atheists. If atheism is taken to be a view, namely the view that there is no God, then atheists must shoulder their share of the burden of proof to support this view. But many atheists admit freely that they cannot sustain such a burden of proof. So they try to shirk their epistemic responsibility by re-defining atheism so that it is no longer a view but just a psychological condition which as such makes no assertions. They are really closet agnostics who want to claim the mantle of atheism without shouldering its responsibilities. This is disingenuous and still leaves us asking, "So is there a God or not?"10

Indeed, that is the question. Does God exist or doesn't He? Rigging the debate by redefining one's position so as to make it the winner by default is no way to resolve this question. It must be resolved by an examination of the evidence. If good evidence exists against God's existence, we should conclude God does not exist. If good evidence exists in favor of God's existence, we should conclude God exists. But we cannot conclude anything in the absence of evidence. That is what the presumption of atheism does, and that is why it should be rejected as a viable definition of atheism.


1. William Lane Craig, during an interview with Lee Strobel, “Bill Craig on the New Atheism,” available from; Internet; accessed 18 March 2009.
2. While Flew used the etymology of the word atheism to justify his notion of non-theist, atheism actually is a composition of the Greek negation a, and theos (God). It literally means not God, or no God. It does not mean non-theist.
3. William Lane Craig and J.P. Moreland, Philosophical Foundations for a Christian Worldview (Downers Grove, IL: InterVarsity Press, 2003), 156.
4. Ibid.
5. Kai Nielsen, Reason and Practice (New York: Harper & Row, 1971), 143-44.
6. Paul Copan, "The Presumption of Atheism"; available from; Internet; accessed 13 February 2005.
7. William Lane Craig and J.P. Moreland, Philosophical Foundations, 156.
8. Paul Copan, "The Presumption of Atheism"; available from; Internet; accessed 13 February 2005.
9. William Lane Craig and J.P. Moreland, Philosophical Foundations, 157.
10. William Lane Craig, "Definition of Atheism"; available from; Internet; accessed 12 September 2007.

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