The most fundamental disagreement between atheists and theists is over the existence of a divine being. The term “atheist” describes a person who does not believe that there is such a being. Worldwide there may be as many as a billion atheists, although social stigma, political pressure, and intolerance make polling difficult.
We can use the term “God” to describe the divine entity that is a central tenet of the major monotheistic religions—Christianity, Islam, and Judaism. At a minimum, this being is understood as having all power, all knowledge, and being infinitely good or morally perfect. We can also use the “gods” to describe all other lesser characterizations of divine beings.
The God concept is the focus of philosophical arguments for and against theism for several reasons. First, that being is the essential, common thread in the western monotheistic traditions, as mentioned above. More than 3 billion people now can be said to subscribe to the view that God exists, and countless more in the past have agreed. Furthermore, the existence of such a being, more so than any other lesser characterization, would have profound metaphysical, personal, moral, social, and historical implications. Without exaggeration, the existence of such a being would be the single most important fact ever acknowledged by human beings. Another motivation for focusing atheistic arguments on the notion of a divine being that embodies conceptual absolutes as the omni-God does, is that by implication many of the conclusions we can draw about that being will will apply a fortiori to other, lesser beings. And a being that is not the positive culmination of all possible power, knowledge, and goodness, it has been argued, would not be worthy of the title “God” and would not be worthy of our attention. Many atheists and monotheists have agreed on at least this much.
We can make two useful pairs of distinctions concerning the term “atheism.” It has come to be widely accepted that, at a minimum, to be an atheist is to lack a belief that a God or gods exist. We can follow Antony Flew and label this inclusive sense of the term as negative atheism. Parallels for this use of the term would be terms such as “amoral,” “atypical,” or “asymmetrical.” To identify something as atypical or asymmetrical only indicates that it is does not have something. Contrast “amoral” with “immoral.” Non-human animals like fish are amoral. (Perhaps by they are negative atheists too). But only a person who is capable of moral behavior can be immoral. So negative atheism would includes someone who has never reflected on the question of whether or not God exists and has no opinion about the matter. It would also include someone who had thought about the matter a great deal and has concluded either that she has insufficient evidence to decide the question, or that the question cannot be resolved in principle. Both people lack a belief in God, but in importantly different ways. So the position traditionally characterized as agnostic—neither believing that God does exist nor believing that God does not exist, is a negative atheistic position.
A positive atheist then, is someone who possesses the belief “God does not exist.” Beyond lacking a belief inGod, they will deny the truth of the claim, “God exists,” and affirm that there is no such thing. So positive atheists are negative atheists, but negative atheists need not be positive atheists. An analogy is useful. If a person believes that there is no such thing as unicorns, then she is a positive atheist concerning unicorns. Someone who has never heard of them would be a negative atheist with respect to unicorns. So would a person who has thought about the question, and is not sure whether they exist or not.
A person’s atheism can be narrow or wide in scope depending upon the sorts of entities at issue. The narrow atheist lacks a belief about or denies that existence of God. A wide atheist lacks a belief about or denies the existence of all gods, including but not limited to the traditional omni-God. The wide positive atheist, then, would actively deny that God exists, and also deny that Zeus, Gefjun, Thor, Sobek, Bakunawa and others exist. The narrow positive atheist merely denies that God exists, without taking a stronger view about the existence or non-existence of other supernatural beings. One could be a narrow atheist about God, but still believe in the existence of some other supernatural entities.
Separating these different senses of the term allows us to better understand the different sorts of justification that can be given for varieties of atheism with different scope. An argument may serve to justify one form of atheism and not another, for example, or an argument, while itself focusing on one account of God, may serve equally well against other conceptions. Keeping the positions and the justifications that can support them is particularly important given how many people have doubts about being able to “prove a negative.”
Approaches to the Question
Justifications for atheism have taken forms that can be usefully divided into several categories. For the most part, atheists have taken an evidentialist approach to the question of God’s existence. That is, atheists have taken the view that whether or not a person is justified in having an attitude of belief towards the proposition “God exists,” is a function of that person’s evidence. Towards that end, they, at least the positive atheists, have sought to develop arguments that would serve as evidence to justify concluding that God does not exist. An asymmetry that exists between theistic accounts of belief and atheistic accounts of non-belief is that atheists have not, for the most part, offered faith as a justification.
Atheists have offered a wide range of arguments and justifications for non-belief. One important exception appears to be Antony Flew’s presumption of atheism in God, Freedom, and Immorality: A Critical Analysis. Flew argues that the default position for any rational believer is neutral with regard to the existence of God, and to be neutral is to not have a belief regarding its existence. "The onus of proof lies on the man who affirms, not on the man who denies. . . on the proposition, not on the opposition,” Flew argues. Beyond that, coming to believe that such a thing does or does not exist will require justification, much as a jury presumes innocence concerning the accused and requires evidence in order to conclude that he is guilty. Flew’s negative atheist will presume nothing at the outset, not even the logical coherence of the notion of God, but her presumption will be defeasible, or revisable in the light of evidence. Let’s call this view atheism by default.
The Atheism by Default position contrasts to a more permissive attitude that many people take regarding religious belief. The notions of religious tolerance and freedom are sometimes taken to indicate the epistemic permissibility of believing despite a lack of evidence in favor or even evidence to the contrary. The general principle seems to be something such as, until one has evidence to the contrary, it is epistemically permissible, or in no violation of an epistemic duty, to believe a proposition. In contrast to the jury model, this view treats religious beliefs as reasonable until proven guilty. To say the least, this sort of epistemic policy about God or any other matter has been controversial. We typically do not take it to be epistemically inculpable or reasonable for a person to believe in Santa Claus, the Tooth Fairy, or some other supernatural being merely because they do not possess evidence to the contrary. Consider whether or not it is reasonable for a person to begin believing that they have cancer because they do not have evidence to the contrary.
There is a family of arguments, sometimes known as deductive atheology, for the conclusion that God is impossible. Another large group of important and influential arguments can be gathered under the heading inductive atheology. These arguments invoke considerations about the natural world that we have discovered that make belief in God unreasonable. Another approach, atheistic noncognitivism, denies that God talk is meaningful or has any propositional content that can be evaluated in terms of truth or falsity.
Rather, religious speech acts are better viewed as a complicated sort of emoting or expression of spiritual passion. Inductive and deductive approaches are cognitivistic in that they accept that claims about God have meaningful content and can be determined to be true or false.
There is nothing to preclude an atheist’s taking some of these different approaches in conjunction, or adopting one type of argument about a set of God claims and another about the others.
There is a difference between arguing that a given proof for the existence of God suffers from some fatal flaw or flaws, and arguing more generally that there is no God or gods. The implication of the former would only be that that alleged proof does not succeed, not that no God exists. One form of negative atheist, then, would be the person for whom all of the arguments for the existence of God (that she is aware of) appear to suffer from some fatal flaw(s). Smith has read and discussed the question widely and for every argument she has encountered in favor of God’s existence it has seemed to her that there is some serious problem or other that undermines it. As a result, she lacks a belief that God exists. Whether or not positive atheism can be justified in a similar situation is a more complicated matter. It is unclear exactly what, if anything, one can infer generally from the failures of some arguments for X about the prospects of all arguments for X. There is surely some point at which it is reasonable to conclude from our failures to find evidence for Santa Claus, Bigfoot, or an existing Tyranosaurus Rex, that there exists no such thing. But that broader conclusion will arise from inadequate evidence for the existence combined with theoretical principles about standards of epistemic justification.
An argument or arguments for the conclusion that God does not exist, if successful, will provide the positive atheist with justification. And such an argument could be coupled with conclusions that the reasons given for the existence of God are faulty. Or an argument for God’s non-existence could be compelling grounds that all arguments alleged to prove the existence of God must be based upon fallacious reasoning or false premises.