Understanding Reason and Faith

The debate between faith and reason is in many ways the decisive battleground in the debate between theism and atheism. This is because most defenses of theism appeal to the inadequacy of reason. Typically these defenses will take the form of claiming that there are appropriate spheres for reason, and appropriate spheres for faith, and that belief in God comes from recognizing the appropriate role for faith and the associated “limitation” of reason. Some theists argue that one can believe in God using both faith and reason. Once again, we should define our terms.1Faith means that one considers a particular claim (e.g., “God exists”) to be actual knowledge, absolutely certain knowledge. This claim to certainty is held in the absence of adequate evidence, or in direct contradiction to the evidence. Evidence is considered relevant only in so far as it supports the proposition; and irrelevant or inadequate to the extent that it does not support the proposition.

“Faith” has multiple usages, and often in debates the meaning shifts. For example, a theist might state that an atheist has “faith” too. For example, the atheist has “faith” that the sun will come up tomorrow or that the airplane one is about to get into won’t go down in flames. Clearly, this is not the same sense of the word that theists use when they say that they have “faith” that God exists. For example, one can be virtually certain that the sun will come up tomorrow, and this comes from evidence analogous to a repeatable experiment: everyday the sun has come up. Of course, it is not certain; an unanticipated event like the sun exploding could force us to revisit our expectations. The airplane example is yet another case of reasonable expectations based on historical evidence, and the (fortunately rare) exceptions are clear reasons why we can never be truly certain when boarding a plane that it in fact won’t go down. The theist, however, is absolutely certain that God exists, absolutely certain that no future evidence will appear that would change his or her mind.

“Reason” means the application of logical principles to the available evidence. While the principles of reason / logic are certain, the conclusions one obtains from them are only as certain as the underlying assumptions, which is why science is rarely, if ever, absolutely certain (though in many cases, its theories are certain to a very high degree of probability). In fact, scientific theories are rarely “deduced,” but are, instead, “inferred”; that is, they are based on inductive logic, or generalizing from specific examples. The “inferred” theory, if it is any good, will make independently testable predictions, and will explain a range of phenomena that had seemed unrelated before. When multiple, independent tests corroborate a theory, it can, just from a statistical standpoint, become virtually certain. 2

The critical point here is that while almost nothing is certain, everything is not equally uncertain. Our theories can be ranked by the evidence supporting them, and our degree of “belief” should be similarly ranked; that is, we “believe” in proportion to the evidence—all the way from “completely unsubstantiated” to “some possibility” to “virtually certain.” Compare, for example, the theory that leprechauns really do exist with the Germ Theory of Disease. Neither one is certain, but one is far closer to being certain than the other.

I stated that the principles of logic are “certain.” This touches on a particularly important part of the faith vs. reason debate. Often, the advocate of faith will say, “But you can’t prove the truth of logic, so you must have “faith” in it—just as I have faith in God.” This critique of reason brings to mind the story of the child who keeps asking “why?” to every answer offered by the parent. Of course, this infinite regress of cause and effect cannot go on forever. To understand when to stop asking “why?” is to begin to understand the nature of concepts. Concepts do not exist in a vacuum. With one class of exceptions, concepts derive their meaning from some immediately ancestral set of concepts and can retain their meaning only within that context. You hit “bedrock” when you reach the so-called axiomatic concepts, which are irreducible, primary facts of reality—our “percepts.” These percepts form the foundation upon which we build our concepts. How do you know when you’ve finally hit these primary facts of reality in the long string of why’s? You know—and this is critically important—when there is no way to deny them, or even to question them, without presupposing that they are, in fact, true. To deny them or to even question whether they are true is to literally utter a contradiction.

This “bedrock” test is very specific.  Let’s illustrate it with an example. Suppose I say, “Logic is an arbitrary human invention and could be wrong.” Well, if it is wrong, then the Law of Contradiction (a thing cannot be itself and its negation at the same time and in the same respect) and the related Law of Identity (a thing is itself) are wrong; but then that means the very words that make up my original claim, such as, “Logic is arbitrary” could mean “Logic is not arbitrary” or it could mean both at the same time and in the same respect. In fact, it could mean “I like chunky peanut butter.”  If all that sounds crazy and unintelligible, that’s because it is, as are all utterances when the truth of logical principles cannot be assumed.  The point here is that without the assumed truth of logic, language itself becomes impossible. So the contradiction is this: For my original statement to have any meaning at all, logic has to be true, but the content of my original statement questions that truth: a self-contradiction. Logic, then, is not accepted on “faith” but as a necessary, self-evident truth, something that is required to speak or think at all. The same can be shown for the concepts of existence, consciousness, and the reliability of our senses. Again, there is no way to talk about any of these things being possibly untrue without first requiring them (implicitly) to be necessarily true.

In life one is exposed to claim after claim (Aliens, Heaven’s Gate, Pyramid Power, ESP, etc). What criteria should we apply to separate claims that correspond better with reality from others that do not? To use an earlier example, how do we decide that the Leprechaun theory should not be taken just as seriously as the Germ Theory of Disease? The answer is that we know by applying the standard of reason. If faith were a viable alternative to reason, then what are its rules? How do we know when to apply it? How do we know when someone has misapplied it? How can we tell the difference between the effects of faith and the effects of inadvertent, though well-meaning, self-delusion? Indeed, how can we test its validity?

Let’s illustrate this problem.  A member of Christian sect X believes that all other sects are damned, and she says that she knows this through faith. The person she is talking to is a member of sect Y that believes only sect Y is the one true faith, and that all others are damned, including members of sect X—and, of course, she knows this through faith.   Clearly they both cannot be right. The member of sect Y asks the member of sect X how she knows that she is not really just hearing the deceitful voice of Satan leading her down a false path. To that our sect X member confidently replies, “I know that through faith as well.” Not surprisingly, these are the same answers given by the member of sect Y to exactly the same questions regarding her confidence in the truth of her favorite sect.  There is no independently validated method to resolve this. If reason is not the standard, then there literally is no standard, and people who abandon it have simply written themselves a blank check to believe whatever they choose. Cloaking this irrationalism with comfortable terms like “faith” does not make it any less irrational. As John A. T. Robinson once put it: “The only alternatives to thinking with reason are thinking unreasonably and not thinking.” 3

1 George H. Smith, Atheism: The Case Against God (Amherst: Prometheus Books, 1989), gives an excellent introduction to this critical subject. I draw from Smith both here and below, in my discussion of axiomatic concepts, and Smith is drawing from the Objectivist epistemology of Ayn Rand.

2 Philosopher of science, Philip Kitcher, in his Abusing Science: The Case Against Creationism (Cambridge: The MIT Press, 1993), from which I am drawing these points, gives an outstanding introduction to the methodology of science.

3 Quoted in Smith, op. cit.  p. 110.

Atheism, Agnosticism, and Burden of Proof

“How can you be an atheist if you cannot disprove the existence of God?” This all-too-common question is often related to a misunderstanding of the concept of burden of proof, of how that concept relates to belief, and of how both of these ideas relate to the definitions of agnosticism and atheism.

Burden of Proof

You have probably heard the term “burden of proof” used in courtroom settings, often in the context of a criminal trial where the accused is innocent until proven guilty. What this means, of course, is that the accused’s innocence is assumed to be true, unless someone can actually prove otherwise. In other words, the accused’s innocence is the default position. As a result, it is absolutely not required for the accused to prove his innocence; he has only to show that, based on the prosecution’s case, there is no good reason to believe in his guilt; that the arguments and evidence presented by the prosecution are either unreliable, or do not make his guilt any more likely than some alternative explanation. Simply put, the burden of proof is on the prosecution.

Importantly, when a jury returns a finding of “not guilty” they are not saying that they believe the suspect is innocent beyond a reasonable doubt. They may have a truckload of doubt about his innocence. Their finding means only that reasonable doubt exists as to the suspect’s guilt. If there is such reasonable doubt and the burden is on the prosecution, then the jury is ethically and rationally required to acquit.

Why do we put the burden of proof on the prosecution? Because otherwise the prosecution’s job would be much too easy. For example, imagine you had to prove your innocence against the charge that you have the supernatural ability to cause cancer in humans anywhere in the world, and that you actually use this ability for your own sadistic pleasure, which is behind all the world’s cases of previously unexplained cancers. To make their case the prosecution puts you on the stand and asks, “Well then, if you aren’t guilty, how do you explain all the cases of mysterious cancers?” Helplessly, you admit that you can’t, to which the prosecution replies with an accusing finger, “Ah ha!” With your fear and frustration mounting you ask, “What makes you think it’s me!?” The prosecution immediately points out that Analogyland is not a country like the US: here you are guilty until proven innocent, and so the prosecution does not have to explain or prove anything. On the contrary, it is you that has to do the explaining. Nonetheless, the prosecution is feeling a bit generous and they volunteer that they are charging you based on their own psychic powers, powers that give them direct knowledge of evil people like you. When you ask what evidence they have that such a psychic sense is even reliable, they angrily warn you that your attempts to confuse the court will not be tolerated. The prosecution then reminds you once again that the only party who must present evidence is you, and that if you cannot prove the prosecution wrong, you are guilty by default.

Needless to say, you would be doomed in such a situation. In fact, in any land where your guilt is the default assumption, you would be doomed to a guilty verdict whenever the charge against you was unprovable, and the list of unprovable charges is limited only by one’s imagination (e.g., you are a witch who magically eliminates all evidence against her, or the reincarnation of Hitler pretending to be a good person, or an evil deity whose pretense at being a normal person is just what one would expect, etc., etc.). As you can imagine, in such a land you could easily send anyone you didn’t like to prison by dreaming up some unprovable claim; and, of course, they could do the same to you. One doesn’t have to look too far into history to find examples of this, such as the famous Salem Witch Trials.

To clarify the issue even more let’s leave the courtroom setting all together and just look at some off-the-wall factual claims that someone who comes knocking at your door might make. Let’s say someone, who calls himself Contactee Bob, knocks on your door and claims that leprechauns are real, but they are so smart and powerful they know how to avoid most human contact. However, Bob explains, leprechauns do make direct telepathic contact with a few deserving humans. When these leprechauns reveal their existence through such telepathic communication, the humans on the receiving end experience it as direct, revealed knowledge of the leprechauns’ existence. Bob claims to be such a contactee and hopes that one day you will be too. “Think positive leprechaun thoughts,” says Bob, “and you will be contacted too!”

At the end of his speech you ask Bob how he knows there aren’t alternative explanations of his “revealed knowledge” experience that are at least as probable as his leprechaun explanation (such as an obvious psychological one). Bob has heard this before, of course, and he’s ready: “Okay, Mr. Skeptic, prove there are no leprechauns.” Bob has even studied the contactee apologetic literature and takes his objection a step further: “If you claim that there are no leprechauns, then that implies you are omniscient since you would have to have knowledge of all parts of the universe to know that there are no leprechauns anywhere in it.”

This last statement of Bob’s would actually be true if the burden of proof were on you to disprove his claim, rather than on him to prove it. Bob has shifted the burden of proof onto you, the innocent bystander being subjected to his claims. He is arguing that his claim must be considered true by default unless you can disprove it, while all he has to do is watch you flounder in the attempt. What Bob probably doesn’t realize, however, is that in order for him to consistently hold such an interpretation of burden of proof, he would have to believe everything that he couldn’t disprove. While his interpretation of burden of proof lets in his leprechauns, it does so at the price of letting in an unimaginably large army of other bizarre creatures from the depths of human imagination and mythology. Consider the implications of this. Just to amuse yourself you could dream up claims of your own and present them back to Bob, claims like, “there are undetectable trans-dimensional hyper-intelligent fish all named, curiously enough, Wanda,” “There is an invisible, 3-headed dragon named Morris Minor who is a Douglas Adams fan and is responsible for manipulating the weather in such a way that it appears to be almost, but not quite, entirely unpredictable,” etc., etc., and Bob, by his understanding of burden of proof, would have to believe them all simply because he could not disprove any of them. This is what follows when the concept of burden of proof is misapplied or ignored. Clearly, this way madness lies.

What is the common element in the courtroom and Contactee Bob examples? It is that in both cases the burden of proof is not on the person making the positive claim. Now, by “positive” claim I mean any truth claim, such as “X is true” or “X is false.” Notice that saying something is false is also a positive truth claim: you are claiming that the assertion “X is false” is a true statement (i.e., you positively disbelieve X). For example, the claim “leprechauns do exist” is just as positive a claim as is “leprechauns do not exist.” Each is a claim to truth, and the burden of proof properly lies with the person making either claim.

But wait a minute. Doesn’t this take us right back to where we started? Doesn’t this mean that if I lack belief in Bob’s claims, then I have a burden of proof on me to prove him wrong just like he argued? Well, that depends on what you mean by “lack belief.”

Absence of Belief vs. Disbelief

A new born baby lacks belief in quite a bit, including the concept of God. Obviously, however, this is not the same thing as saying the baby disbelieves these claims (i.e., believes that these claims are false); the baby is merely absent belief—due in this case to its lack of awareness of the very concepts in question. Similarly, an adult who has grown up deep in an Amazonian jungle, and who has never even heard of people existing outside the jungle (let alone of such outsiders’ religions) is certainly absent belief in the Judeo-Christian God; however, once again, one could not say that this Amazonian regards God with positive disbelief, only that he is absent belief—due in the case to his never having been introduced to the idea.

In each of these examples, the individuals lack awareness of the concept of the Judeo-Christian God. Clearly, it makes no sense to say that they believe the claim “God exists” is false. On the other hand, it also makes no sense to say that they believe the claim is true. As a result, we cannot call them theists, and, depending on how one defines the term, we may not be able to call them atheists either (we’ll explore this a bit more later). But we can say that they are absent belief.

Note that in the preceding examples it also makes no sense to say that these individuals believe that the probability that God exists is around 50%. This leads us to a third sense in which one could be said to be absent belief in a claim. This occurs when there is at least some evidence for a claim, but this evidence is offset by equally strong evidence for the falsity of the claim or for alternative explanations. In other words, on balance, the claim is seen as somewhere around 50% probable. In such a case one would be rationally justified in “suspending judgment,” in making no commitment at all. If we’re talking about the claim that the Judeo-Christian God exists, then, as in the prior cases, we cannot call a person holding this view a theist.

One thing should be clear from the preceding discussion. We all start out at some point in our lives from the position of absence of belief due to absence of information. Clearly there is no burden of proof on individuals in this “position” (really a non-position). They are, as it were, simply waiting for input. It would be irrational for such people to claim to believe one way or the other. However, while you start out in life by justifiably saying, “the burden of proof is on you Mr. Positive Atheist and Ms. Theist,” as soon as attempts are made to meet that burden, the ball is right back in your court. You will need to assess the arguments and then assess the probabilities that the claim is true or false. Importantly, as the last of the earlier examples demonstrates, absence of belief may be the result of just such a reassessment: it may indicate not the default starting position of ignorance, but a reasoned, defensible conclusion that the odds of the claim’s being true is around 50% (not a view that I happen to share, by the way). In this special case, one is making a positive claim that the arguments and evidence support even odds.

Believing in Proportion to the Evidence

At this point all we have said is that one believes, disbelieves, or is absent belief in some claim. We’ve also suggested that this latter state is due either to ignorance of the claim (no burden of proof) or to an assessment that the probability of its being true is around 50% (carries a burden of proof).

This notion of probabilities of truth is much closer to the way science actually works than it is to the simplistic notions of absolute proof and absolute disproof, with everything in between treated as “unknown,” or “speculative.” Looking at truth values in this probabilistic fashion suggests a continuum; and assuming we believe only when we are rationally justified to do so, our “beliefs” cannot simply be “on” or “off.” Instead, our beliefs are a function of the probability that they correspond to factually true statements: the higher the probability, the more we believe; the lower the probability, the less we believe; and the lower still, the more we disbelieve.

So, what affects the probability that a claim is true? Certainly direct evidence, both for and against, directly affects it, including such things as the claim’s predictive success and explanatory power; but it is important to recognize that background knowledge is also an extremely relevant form of evidence. By “background knowledge” we mean the entire database of well-confirmed human knowledge.

Some claims, if true, would require that we throw out some of this well-confirmed background knowledge. To be sure, having to throw out cherished parts of our background knowledge is not unknown in history, but it occurred only when the evidence behind such a revolution was truly overwhelming. For example, if some theory is extremely well supported (say, at better than 99.9% as in the case of the Theory of the Atom), then any new claim that entails throwing out this part of our background knowledge needs to be supported by even better evidence than that supporting the existing theory. If weak or no evidence is offered, then should we remain absent belief in this new claim, as if the probability were around 50%? Definitely not. Why? Because the evidence against the claim is the evidence we already have for the background knowledge, which means the probability that the claim is true, in the absence of strong evidence, is extremely low.

There are also claims that, while not contradicting background knowledge, are completely unconnected to it, or go well beyond it in some radical way. But here again, the fact that a claim is “out of nowhere” does not make it false, though it does raise the evidentiary bar. Examples of this include certain notions of “supernatural” (specifically those that do not entail a logical contradiction as does the Judeo-Christian God). For example, while it doesn’t directly contradict our background knowledge, a claim that an intelligent, extraordinarily powerful alien somehow “started” the world 5 billion years ago is certainly a claim that is not in any sense a plausible extension of our background knowledge; it resolves no mysteries (other than replacing current mysteries with even bigger ones); and it lacks even suggestive support either directly, or indirectly from our background knowledge.

Now this latter situation is particularly interesting for a number of reasons: the claim is logically possible, it has no negative evidence against it, and it conflicts with no part of our background knowledge. On the other hand, it is has no evidence for it, not even the mild suggestive support that comes from its being plausibly related to, or extended from, our background knowledge. The question then is should we consider such an “out of nowhere” claim as having a 50% probability of being true? Should we say that it is as likely to be true as not? Definitely not. Why? Because the only thing such a claim has going for it is mere logical possibility. However, the list of the logically possible is effectively infinite. Since there is good reason to believe that the set of all factually true statements is vanishingly small compared with the set of all logically possible statements, then the odds are vanishingly small that some “out of the blue” logically possible statement would actually correspond to a fact of reality. Without some evidence supporting a claim there is no reason to believe that the odds favoring its factual truth are different than the odds favoring the factual truth of a randomly constructed logically possible statement, and the odds of that are effectively zero. Therefore, we have to conclude that an entirely unfounded claim—even in the absence of negative evidence—deserves not simply suspension of belief, but actual disbelief.


Of course, if a claim is not even logically possible, then all this talk about probabilities becomes moot. In such a case I can be absolutely certain (100% probability) that a claim is false—without any evidence at all. A claim is logically impossible when it is self-contradictory (also called incoherent). For example, if you claim that there exists a married bachelor or a triangular square, then the probability that you are wrong is 100%. Of course, these examples are obviously incoherent; however, many claims are no less incoherent, though this fact is far less obvious. That’s where careful analysis comes in. When such analysis shows that some claim entails a logical contradiction, then one can be sure that the claim is false—again, without introducing evidence at all. This kind of evidence-independent argument is referred to as an a priori argument: it is based on logic alone.

Belief vs. Knowledge

So far, we have been talking about rationally justified beliefs. To be sure, beliefs are often held without rational justification—even without the pretense of rational justification, such as when people talk about believing something “on faith.” This subject is dealt with elsewhere1, so I won’t repeat it here beyond noting that faith is not a justification, but an admission that there is no justification. If there are rational reasons to believe something, then “faith” is superfluous. If there are no rational reasons to believe something, then continued belief is, by definition, irrational. Clothing irrationalism with the more comfortable term “faith” changes nothing. Indeed, free of the restrictions of rational justification, I could have faith that the tooth fairy is real, or any of the world’s sundry gods, goddesses, wood nymphs, and other human imaginings. The problem is that there are no independently validated rules that govern the use of faith, which makes it a kind of blank check. As a result, faith allows in God—along with any and everything else. Reason is the only validated means we have to qualify a belief as actual knowledge, the only means we have to separate the “wheat from the chaff.”


Some so-called claims are not really claims at all. Claims made with meaningless terms amount to nothing more than a kind of noise. Examples include, “xonipboo loves you” and “myrssla exists.” There not only is no actual evidence for or against such statements, there is no conceivable evidence that would count for or against them; consequently, they are factually meaningless. Since such a claim asserts nothing, then it means nothing to say one believes that a factually meaningless claim is either true or false—to any degree at all. The subject of such statements does not even have a referent. If I say I believe in “it” (or don’t believe in “it”), then I literally cannot know what I am talking about—I literally have no idea just what it is that I think I believe (or disbelieve) in.

Defining Atheism and Agnosticism

Pulling all these ideas together, we can now make what I hope are more useful and more accurate definitions of atheism and agnosticism.

At the most literal level, atheism can be analyzed as follows: “a” means without, and “theism” means belief in God. So, literally “atheism” means without belief in God. “Theism” of course, means with belief in God. Now, one either believes in the Judeo-Christian God or one does not. If one does, then one is a theist; if one does not, then one is an atheist. Technically, then, the terms “theism,” and “atheism” are mutually exclusive and jointly exhaustive—there is no third alternative. Even the case of absence of belief falls under atheism, since absence of belief means absence of belief in God—that is, without belief in God. Since such persons are clearly not theists, they are (literally speaking) a-theists.

Of course, while literally true this definition does not really capture the typical modern usage of the term “atheism.” Indeed, under this definition all newborns would be considered atheists, which seems inconsistent with the way people usually understand the term. The most simplistic understanding of the terms “theism” and “atheism” in common usage is that atheists are absolutely sure that there is no God, while theists are absolutely sure that there is. Everyone else would be considered some flavor of agnostic. Interestingly, “agnosticism” once referred only to the view that some particular claim is unknowable. Under this definition many believers would be, in fact, agnostics, or more specifically, agnostic theists; they agree that God’s existence is unknowable, but they believe anyway on faith, while agnostic atheists reject faith as invalid, and so remain absent belief. So, under this view “agnosticism” refers only to one’s views about knowability, and not to one’s beliefs. However, this usage of the term “agnosticism” also doesn’t seem to reflect typical modern usage. Currently, the term seems to refer to the view that one neither accepts nor rejects God’s existence because God’s existence is unknowable. There is also the more general term, “negative atheism,” which refers only to the first part of that definition: that one can neither affirm nor deny God’s existence—for whatever reason. However, “agnosticism” is sometimes used in that more general sense as well, in which case it is synonymous with “negative atheism” (I use “agnosticism” in this latter sense—as synonymous with negative atheism). Negative atheism is the position that one should not believe, not that one should disbelieve. Positive atheism, on the other hand, argues that one should positively disbelieve—that is, one should believe that the claim, God exists, is false.

These more popular definitions leave a few gaps; for example, they all seem to implicitly assume that everyone is familiar with the subject matter and the arguments. If so, then what about our newborns, and those who have never been exposed to Judeo-Christian theism? Well, if they lack belief, which they do, then they are not theists; however, they do not disbelieve in God, so they are not positive atheists either. Therefore, they are a kind of negative atheist—but it’s the uncritical, uninformed kind and this is usually made clear just by qualifying one’s usage of the term with just such modifiers. Additionally, these popular definitions do not address whether the views are justified by appeal to reason. To be sure, people can be found in each of these categories whose beliefs have nothing to do with reason. For example, some ardent positive atheists have no rational justification for their views at all—perhaps because they are postmodernists or social constructionists, or because of political dogma, or because it’s part of the doctrine of some earth-spirit religion that they accept on faith, etc. Similarly, many theists openly reject reason, and even seem to find delight in saying that they believe despite flagrant logical contradictions—contradictions that they are all too happy to admit to. Where this distinction must be made—between appealing to reason and flouting it—the words “critical” or “rational” are often introduced, such as “critical positive atheist.”

If we take these definitions, and the caveats just mentioned, and couple them with our earlier discussion about believing in proportion to the evidence—that is, viewing “truth” as a probabilistic function of all relevant evidence and knowledge—then we can summarize everything into the following chart2:


Primary Term Other Common Terms Attitude Evidence Description
Positive Atheism Atheism Rejection Absolutely disprovable Logical impossibility
Positive Atheism Atheism Rejection Completely unfounded No direct or indirect support at all, even though there is no negative evidence
Positive Atheism Atheism Rejection Empirically disprovable Logically possible but odds are very close to 0
Negative Atheism Agnosticism Skepticism Empirically unlikely Odds are low
Negative Atheism Agnosticism Uncommitted Empirically indeterminate Substantial evidence, but about equally substantial evidence for alternatives
Negative Atheism Agnosticism None No conceivable evidence The claim in question is factually meaningless
Negative Atheism Agnosticism None Unaware of any relevant evidence Has never heard of the claim in question, or has never given it any thought.
Positive Theism Agnosticism / Pragmatic Theism Inclined Empirically likely Odds are high
Positive Theism Theism Acceptance Empirically provable Logically possible that’s it wrong, but odds are very close to 100
Positive Theism Theism Acceptance Absolutely provable Logical necessity



To tie our whole discussion together, let’s apply these ideas to the earlier Contactee Bob example. Contactee Bob doesn’t appear to be claiming something that is logically impossible, but he certainly hasn’t given us any reason to think that his claims are true; that is, he hasn’t given us any reason to suppose that his claims are more probably true than not; consequently, he has failed to meet the burden of proof. So, do I believe that Contactee Bob’s claim is true? No. Do I believe that Contactee Bob’s claim is definitely false? Technically, no, but I am not saying it’s a coin toss either, that it is as likely to be true as false. In the Contactee Bob example, we do have knowledge of background facts that bear on the likelihood of his claim being true. So, while there is no evidence supporting Bob’s claim, there is evidence supporting the alternative claim that Bob has deluded himself. We know, for example, that there are many supposed contactees for many types of strange beings, such as angels, aliens, various gods and goddesses, etc. As a group, these contactees report mutually contradictory experiences—even when the contactees are talking about the very same being. While this doesn’t conclusively prove that Bob is wrong, it is consistent with the alternative claim that all contactees of all of these “beings” have deluded themselves regarding the nature of their experiences. This background evidence, then, makes the competing self-delusion claim far more likely than Bob’s claim.

Bob also argued that it is self-contradictory to deny the existence of leprechauns because such denial implies omniscience; that is, we would need to have knowledge of all parts of the universe to know that there are no leprechauns anywhere in it. Our discussion up to this point should now make clear the fatal flaw in this argument: Bob assumes that absolute disproof is necessary to justify both absence of belief and disbelief. But, as we have seen, one can be absent belief or even disbelieve in the existence of leprechauns without at the same time claiming absolute knowledge that leprechauns do not exist. One should be at least absent belief based on Bob’s having failed to meet his burden of proof. But, when one also considers how this claim fits with our background knowledge and other known facts about claims of this type, then one can go further and have very good reason to suppose that Bob’s claims are extremely improbable, and therefore, to positively disbelieve them.

So, whether people claim that Santa Clause, telepathic space aliens, or God exists, the burden of proof is on them. None of these claims becomes true by default; that is, they do not become true on the grounds that they cannot be disproved. If those making a claim do so in a logically consistent way but cannot meet their burden of proof, then absence of belief is the best that can be rationally achieved. However, depending on other relevant facts (such as background knowledge), we may have good reason to suppose that the claim, while not absolutely false, is probably false in the extreme, thereby making positive disbelief the only rational option. Moreover, if they make a claim in a self-contradictory way, then we can be 100% sure that they are mistaken even without any evidence at all. Finally, there is also another way in which people may make their claims: they can use factually meaningless terms.

It is interesting to note that if one successfully demonstrates that religious terms like “God” are factually meaningless, then one cannot be a positive atheist, since to positively claim that God does not exist implies that the word “God” has meaning. I take the approach, along with Michael Martin3, that one can argue that religious terms are meaningless, and then go on to argue that if we assume, for the sake of argument, that the terms are meaningful, then contradictions immediately follow. So, to the extent I am successful with the first part, I am a negative atheist, and to the extent I am wrong in the first part but right in the second, I am a positive atheist.

1 P. Wesley Edwards, “Reason vs. Faith,” FreethoughtDebater, <http://www.freethoughtdebater.org/?p=107>, 2004.

2 This chart is influenced by something similar in Michael Scriven, “God and Reason,” in Critiques of God: Making the Case Against Belief in God (Amherst, NY: Prometheus Books, 1997), p.109.

3 An excellent, if somewhat advanced, overview of these issues is Michael Martin, Atheism: A Philosophical Justification, (Philadelphia: Temple University Press, 1990). A classic, and very easy to read work that hits the same points is George H. Smith’s, Atheism: The Case Against God, (Amherst: Prometheus Books, 1989).

Complexity, Probability, and God

A very old, highly intuitive, and still common argument for the existence of God is the Argument from Design.  The thrust of the argument is that the ordered complexity exhibited by the universe as a whole, and in particular by living things, is evidence that there must be an intelligent designer, since the existence of such complexity cannot be otherwise explained.The word “design” as used in this argument refers to the order and incredible complexity not just in biological systems, but also in the very intricate laws of nature that operate throughout the universe.  But, of course, “design” and “complexity” are not the same.  The theist can’t just point to an example of complexity and say, “See, it’s complex, so it is designed.”  That’s just question begging; after all, the whole question at issue in this debate is, “Does complexity imply design?”

We should clarify here what it means to say that a thing is complex.  To say a living thing is complex is to say not only that it has a lot of parts, but that the parts are arranged in a way that is unlikely to happen by chance and those same parts cooperate in a functional way.  For example, in living systems the various parts work together to do such things as run, swim, and fly—let alone live.  Complex non-living systems in the context of the design argument are usually restricted to those that appear to serve a purpose, such as the system of “parts” called the Solar System, which is so configured that the earth is kept at just the “right” distance from the sun to maintain its orbit.The flaws in the Argument from Design are several.  First, using the existence of complexity as a proof for God amounts to a self-contradiction; second, a common form of this argument (made famous by William Paley) misunderstands how humans identify intelligent design; and third, a common version of this argument that is based on probability misrepresents the role of randomness in evolution.1  Let’s look at each of these in turn.

Setting aside any appeal to Darwinism for the moment, what could it possibly mean to say that complexity in living things implies the existence of an intelligent designer like God?  One can only assume that God, whatever that term might refer to, must have at least as much complexity as anything He is supposed to have designed.  Given the theist’s assumption that complexity requires a designer, God’s own complexity implies that He also had a designer.  Either the theist is arguing for an infinite regress of God-designers and designers of God-designers, etc., or he is contradicting his own assumption that complexity requires design.  By using God as an “explanation” the theist is doing nothing more than explaining complexity (in living things) with complexity (God’s).  But this amounts to assuming what one is trying to explain, which is no explanation at all.  It just moves the mystery back a step.

This is the same logical flaw in using God to explain existence itself.  The theist often asks, “If you don’t believe in God, then how do you explain the existence of the universe?”  This question assumes that existence must be caused, and since the universe clearly exists, it too must be caused.  The theist then concludes that God must be that cause.  Now, presumably the theist supposes that God, like the universe, also exists, in which case the theist is right back to violating his own assumptions:  If God exists, and existence must be caused, then by the theist’s own assumption, God must be caused.  By using God as an “explanation” the theist is doing nothing more than explaining existence (the universe’s) with existence (God’s).  And just as before, this amounts to assuming what one is trying to explain.

Typically the theist’s reply to these criticisms is that God is the one exception: All complexity except God’s complexity must be explained, and all existence except God’s existence must be explained.  But this is blatant special pleading.  The theist is simply exempting himself from his own rules:  “Your explanation must meet these conditions; however, my explanation (God) does not.”  Of course, anyone can play this game.  Once could just as easily (and with considerably more parsimony) say all things except the universe as a whole require an explanation.

Even if one wanted to grant the theist his special exemption, other problems remain, which we can see by reviewing what it means to “explain.”  To say that something is “explained” means we’ve moved from the known to the unknown; it does not mean we moved from the unknown to the unknown.  Put simply, you cannot explain a mystery with a mystery.  If someone wants to use God to explain anything, then he would have to understand the mechanisms by which God causes something to happen, but since God is “supernatural,” then this mechanism is inherently mysterious and unknowable.   For example, to use God to “explain” complexity one would have to understand the nature of God’s supposedly uncaused complexity and the means by which it causes complexity in the natural world.  It will not do to say that such understanding is “beyond us,” forever unknowable to our limited intellects, etc.  Doing so would be no different than “explaining” rain by appealing to the mysterious properties of an unknowable rain god.  Explaining mysteries with other mysteries has all the explanatory power of saying, “It’s magic.”

We’ve seen that a supernatural God cannot serve as an explanation for anything, especially if God has the very properties His existence is supposed to explain, like the properties of complexity and existence.  But this is not the only fatal flaw in the Argument from Design.  William Paley made a rather beautiful, highly intuitive, and completely mistaken design argument when he asked us to imagine someone stumbling across a watch lying on the ground, and then carefully examining its mechanism.  He says this person would certainly observe that the watch’s

…several parts are framed and put together for a purpose, e.g., that they are so formed and adjusted as to produce motion, and that motion so regulated as to point out the hour of the day; that if the different parts had been differently shaped from what they are, of a different size from what they are, or placed after any other manner, or in any other order, than that in which they are placed, either no motion at all would have carried on in the machine, or none which would have answered the use that is now served by it…[Therefore] there must have existed…an artificer or artificers, who formed it for the purpose which we find it actually to answer; who comprehended its construction, and designed its use.

Paley then draws his eloquent and persuasive analogy:

…every indication of contrivance, every manifestation of design, which existed in the watch, exists in the works of nature; with the difference, on the side of nature, of being greater and more, and that in a degree which exceeds all computation.

One crucial problem with Paley’s argument is that it assumes humans determine whether or not something is designed by seeing if it has an accurate adjustment of parts—that is, if it shows complexity.  But this is certainly mistaken.  We know that something is designed not by its complexity, or even the degree to which it appears to serve a purpose, but by looking for ways in which it differs from nature.  In other words, nature is the benchmark against which we compare an object to see if it is designed.

For example, many naturally occurring rock fragments just happen to have a sharp edge that is well-suited for serving the purpose of chopping meat, though this does not lead us to believe that these fragments were designed.  Yet, we have found clearly manufactured prehistoric chopping and cutting stones that were designed.  How do we know they were designed and not just examples of fortuitous rock fractures?  Clearly it is not because they are sharp, since naturally occurring rocks are also sharp; and not because they are complex, since they have neither parts nor complexity; and not because they serve a purpose, since obviously random events can make a rock very sharp.  We know these stone hand axes were designed because they have markings on them that differ from what one would find in nature—that is, they have signs of manufacture.

Because the proper criterion for establishing design is difference from nature, and not complexity or apparent usefulness, we can know that something was designed even when it is both extremely simple and has no identifiable purpose at all.  This can be seen when we realize how easy it is to recognize as designed an unidentified simple part from an unidentified machine, such as an L-bracket, or a bit of wire insulation.  If Paley were right, it seems that this should be impossible, since neither purpose nor complexity is apparent.

These examples show that purpose and complexity are not the criteria we use in establishing design.  We know Paley’s watch was designed not because it is complex and/or serves a purpose, but because we recognize it as similar to other products of human manufacture, and / or because of its dissimilarity to anything naturally occurring.  So Paley had it wrong: we don’t know something is intelligently designed because it shows complexity; we know it is designed because it shows signs of manufacture, and the only way we know something is manufactured is by comparing it with nature or by having direct experience of its manufacture.  Now, if the criterion for determining design is comparison with nature, then it makes no sense to apply that criterion to nature itself since nature provides the very benchmark for making the comparison.  But this is precisely what Paley does in order to infer a super-designer.

Even if we ignore this criticism of Paley’s argument (which is decisive on its own), other problems still remain, not the least of which is the analogical form of the argument.  Paley was arguing by analogy.  In other words, since a watch shows adaptation of parts to an end and was designed and built by a designer, then by analogy we observe that nature also shows adaptation of parts to an “end,” and infer that it too must have been designed and built by a designer.  Unfortunately for Paley’s argument, if we consistently apply his analogical reasoning, then we would reach conclusions that he surely didn’t intend.  For example, our only experience with the relationship of designers to their highly complex handiwork, like watches and computers, is that there is a whole team of mortal, imperfect designers of limited power that work on one or very few complex creations—and not one immortal, perfect, and supernatural designer for all complex artifacts. So if Paley’s analogical argument were valid, we would have to conclude that living organisms were made by a team of mortal, non-supernatural, and imperfect creatures, all of whom are limited in their powers, and that different classes of complex things were made by different teams of mortal “gods.”

So far I have argued not only that a supernatural God cannot serve as an explanation for complexity or the existence of the universe, but also that His existence cannot be inferred from these.  So at this point, complexity, particularly the complexity of biological organisms and organs such as the human eye, remains unexplained.  If I were writing before Darwin’s time, I would close at this point with the comment that while we don’t know what the explanation is for the existence of complexity, we do know what the explanation is not—and it cannot be “God.”  Fortunately, however, we are writing after Darwin’s time.  For those readers not familiar with some of the basic tenets of Darwinism I would suggest reviewing the introductory article on this site, Evolution v. Creation, and then the article Evolution: Converging Lines of Evidence.

Often, the creationist will point to the genuinely awesome complexity of something like the human eye, or the bird’s wing, and argue that random chance could never have produced such engineering marvels. The creationist is absolutely correct.  To drive this point home, the creationist then quite correctly likens the odds of a structure like the eye forming by random chance to the odds of a tornado moving through a junkyard and producing a 747 passenger jet.  Again, this is an entirely appropriate analogy. The odds of chance alone producing something as exquisite as the human eye—or even single cell, for that matter—in one step is, for all practical purposes, zero.

Curiously, the evolutionist and the creationist are in complete agreement on this point. The creationist, however, seems to think that it somehow refutes evolution—much to the bewilderment of evolutionists. The reason for this is that the creationist has seriously misunderstood evolutionary theory.   Evolution’s major mechanism, natural selection, is the very opposite of random chance.  Natural selection is all about “cherry picking” and saving useful changes generation after generation.  All random chance provides is, in some sense, the “buffet” from which natural selection can select useful but slight changes.  The critical aspect of this process is that it accumulates these slight changes such that over time the accumulated change is not small at all.

The crucial point here is that there are many, many generations over which this cherry picking occurs, not just one.  To take an extremely simple example, imagine that I have a big box filled with one thousand pennies.  I shake up the box and pick out all the pennies that come up heads, which will be around five hundred (a fifty-fifty chance of coming up heads, so about half of the one thousand pennies): that’s generation one.  I then replace the missing pennies in the box and shake it up and again take out all the heads: that’s generation two.  It’s not too hard to see that in just a few “generations” I would have a pile of several thousand heads-up pennies.  The creationists’ Random Chance criticism applied to this example would amount to pointing to this huge pile of heads-up pennies and saying, “the odds of getting just one thousand pennies to come up heads is one out of a number so large it has three hundred zeros after it, and this evolutionist wants us to believe that with random chance alone he got not just one thousand heads-up pennies but several thousand!”

This imaginary critic’s calculation is absolutely correct. The odds of getting just one thousand heads in one try is so small that if we made a try every second for many billions of years it probably wouldn’t happen even once.  Yet we were able to get not just one thousand, but several thousand heads-up pennies in something like an hour.   Something is obviously wrong somewhere.  That somewhere is in the creationist’s assumption that evolution is supposed to occur in one try and with no selection, which really is analogous to a tornado going through a junkyard and producing a 747.  However, in our pennies example we had more than one try and we got our pile of heads not randomly, but by selecting them non-randomly (by cherry-picking the “good” ones) out of the random variation produced by shaking.  We then saved them up over the multiple tries – adding them to what was saved from previous generations.   Now, keep in mind that in nature, natural selection operates not over a few tries, but over many hundreds of thousands of tries (generations) and over millions, even billions, of years.

Of course, the variation produced by random chance in the pennies example is just heads or tails, and we decided that heads are “better” than tails, so only heads “survive” into the next generation.  Also, the heads-up pennies that make it into the next generation are not more likely to produce heads instead of tails—that is, they don’t reproduce by copying themselves in the way biological systems do.  This is why we won’t get anything complex out of the pennies example, though we do accumulate changes that dramatically “beat the odds.”  Natural selection in biology beats the odds in just this way, but it does so with heredity and a much, much larger range of possible variations than just heads and tails—variations that interact with each other to create many different orders of effects that also interact with each other—that is how biological complexity emerges.  How this process creates complexity is discussed elsewhere on this site, and is even demonstrated through our Freethought Debater version of Richard Dawkins’ Biomorphs program, so it won’t be repeated here.  The point of the preceding discussion is to show another fallacy underpinning the Argument from Design: the misuse of probability when criticizing the theory of evolution.

I have argued that there is no coherent way to use God as an explanation for the existence of complexity since, among other things, God himself is presumably complex.  Similarly, God cannot even be used to explain existence since God, when used as an explanation, presumably exists himself.  I have also argued that Paley’s Watch Argument mistakenly supposes that the existence of complexity and apparent purpose in an artifact are the criteria for establishing that it was designed, and it also makes an inappropriate analogical argument between man-made artifacts and nature.  Finally, I pointed out the most common misuse of probability calculations by theists in their attempts to prove the existence of God and/or attack the plausibility of evolution—namely, that of ignoring the fact that natural selection is not about the appearance of random, spontaneous complexity in one event, but about non-random cumulative selection, which occurs over many, many tries.

1Excellent discussions of the design argument can be found in Richard Dawkins, The Blind Watchmaker (New York: W.W. Norton, 1996), as well as George H. Smith’s, Atheism: The Case Against God (Amherst: Prometheus Books, 1989).  A more technical analysis of these arguments can be found in Michael Martin, Atheism: A Philosophical Justification (Philadelphia: Temple University Press, 1990).