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Monday, July 30, 2007Science And Atheism Are Not Faiths
What is atheism?"
Atheism is characterized by an absence of belief in the existence of gods. This absence of belief generally comes about either through deliberate choice, or from an inherent inability to believe religious teachings which seem literally incredible. It is not a lack of belief born out of simple ignorance of religious teachings.
Some atheists go beyond a mere absence of belief in gods: they actively believe that particular gods, or all gods, do not exist. Just lacking belief in Gods is often referred to as the "weak atheist" position; whereas believing that gods do not (or cannot) exist is known as "strong atheism."
Regarding people who have never been exposed to the concept of 'god': Whether they are 'atheists' or not is a matter of debate. Since you're unlikely to meet anyone who has never encountered religion, it's not a very important debate...
It is important, however, to note the difference between the strong and weak atheist positions. "Weak atheism" is simple scepticism; disbelief in the existence of God. "Strong atheism" is an explicitly held belief that God does not exist. Please do not fall into the trap of assuming that all atheists are "strong atheists." There is a qualitative difference in the "strong" and "weak" positions; it's not just a matter of degree.
Some atheists believe in the nonexistence of all Gods; others limit their atheism to specific Gods, such as the Christian God, rather than making flat-out denials.
"But isn't disbelieving in God the same thing as believing he doesn't exist?"
Definitely not. Disbelief in a proposition means that one does not believe it to be true. Not believing that something is true is not equivalent to believing that it is false; one may simply have no idea whether it is true or not. Which brings us to agnosticism.
"What is agnosticism then?"
The term 'agnosticism' was coined by Professor T.H. Huxley at a meeting of the Metaphysical Society in 1876. He defined an agnostic as someone who disclaimed both ("strong") atheism and theism, and who believed that the question of whether a higher power existed was unsolved and insoluble. Another way of putting it is that an agnostic is someone who believes that we do not know for sure whether God exists. Some agnostics believe that we can never know.
In recent years, however, the term agnostic has also been used to describe those who simply believe that the evidence for or against God is inconclusive, and therefore are undecided about the issue.
To reduce the amount of confusion over the use of term agnosticism, it is recommended that usage based on a belief that we cannot know whether God exists be qualified as "strict agnosticism" and usage based on the belief that we merely do not know yet be qualified as "empirical agnosticism."
Words are slippery things, and language is inexact. Beware of assuming that you can work out someone's philosophical point of view simply from the fact that she calls herself an atheist or an agnostic. For example, many people use agnosticism to mean what is referred to here as "weak atheism," and use the word "atheism" only when referring to "strong atheism."
Beware also that because the word "atheist" has so many shades of meaning, it is very difficult to generalize about atheists. About all you can say for sure is that atheists don't believe in God. For example, it certainly isn't the case that all atheists believe that science is the best way to find out about the universe.
"What about the term 'freethinker'? What does that mean?"
A freethinker is one who thinks freely -- one who is prepared to consider any possibility, and who determines which ideas are right or wrong by bringing reason to bear, according to a consistent set of rules such as the scientific method.
The Freedom From Religion Foundation have a "nontract" on what it means to be a freethinker, at: http://www.ffrf.org/nontracts/freethinker.php.
"So what is the philosophical justification or basis for atheism?"
There are many philosophical justifications for atheism. To find out why a particular person chooses to be an atheist, it's best to ask her.
Many atheists feel that the idea of God as presented by the major religions is essentially self-contradictory, and that it is logically impossible that such a God could exist. Others are atheists through scepticism, because they see no evidence that God exists.
There are a number of books which lay out a philosophical justification for atheism, such as Martin's "Atheism: A Philosophical Justification" and Smith's "Atheism: The Case Against God". A few such books are in the document listing "Atheist Media".
Of course, some people are atheists without having any particular logical argument to back up their atheism. For some, it is simply the most comfortable, common sense position to take.
"But isn't it impossible to prove the nonexistence of something?"
There are many counter-examples to such a statement. For example, it is quite simple to prove that there does not exist a prime number larger than all other prime numbers. Of course, this deals with well-defined objects obeying well-defined rules. Whether Gods or universes are similarly well-defined is a matter for debate.
However, assuming for the moment that the existence of a God is not provably impossible, there are still subtle reasons for assuming the nonexistence of God. If we assume that something does not exist, it is always possible to show that this assumption is invalid by finding a single counter-example.
If on the other hand we assume that something does exist, and if the thing in question is not provably impossible, showing that the assumption is invalid may require an exhaustive search of all possible places where such a thing might be found, to show that it isn't there. Such an exhaustive search is often impractical or impossible. There is no such problem with largest primes, because we can prove that they don't exist.
Therefore it is generally accepted that we must assume things do not exist unless we have evidence that they do. Even theists follow this rule most of the time; they don't believe in unicorns, even though they can't conclusively prove that no unicorns exist anywhere.
To assume that God exists is to make an assumption which probably cannot be tested. We cannot make an exhaustive search of everywhere God might be to prove that he doesn't exist anywhere. So the sceptical atheist assumes by default that God does not exist, since that is an assumption we can test.
Those who profess strong atheism usually do not claim that no sort of God exists; instead, they generally restrict their claims so as to cover varieties of God described by followers of various religions. So whilst it may be impossible to prove conclusively that no God exists, it may be possible to prove that (say) a God as described by a particular religious book does not exist. It may even be possible to prove that no God described by any present-day religion exists.
In practice, believing that no God described by any religion exists is very close to believing that no God exists. However, it is sufficiently different that counter-arguments based on the impossibility of disproving every kind of God are not really applicable.
"But what if God is essentially nondetectable?"
If God interacts with our universe in any way, the effects of his interaction must have some physical manifestation. Hence his interaction with our universe must be in principle detectable.
If God is essentially nondetectable, it must therefore be the case that he does not interact with our universe in any way. Many atheists would argue that if God does not interact with our universe at all, it is of no importance whether he exists or not. A thing which cannot even be detected in principle does not logically exist.
Of course, it could be that God is detectable in principle, and that we merely cannot detect him in practice. However, if the Bible is to be believed, God was easily detectable by the Israelites. Surely he should still be detectable today? Why has the situation changed?
Note that I am not demanding that God interact in a scientifically verifiable, physical way. I might potentially receive some revelation, some direct experience of God. An experience like that would be incommunicable, and not subject to scientific verification -- but it would nevertheless be as compelling as any evidence can be.
But whether by direct revelation or by observation, it must surely be possible to perceive some effect caused by God's presence; otherwise, how can I distinguish him from all the other things that don't exist?
"God is unique. He is the supreme being, the creator of the universe. He must by definition exist."
Things do not exist merely because they have been defined to do so. We know a lot about the definition of Santa Claus -- what he looks like, what he does, where he lives, what his reindeer are called, and so on. But that still doesn't mean that Santa exists.
"Then what if I managed to logically prove that God exists?"
Firstly, before you begin your proof, you must come up with a clear and precise definition of exactly what you mean by "God." A logical proof requires a clear definition of that which you are trying to prove.
"But everyone knows what is meant by 'God'!"
Different religions have very different ideas of what 'God' is like; they even disagree about basic issues such as how many gods there are, whether they're male or female, and so on. An atheist's idea of what people mean by the word 'God' may be very different from your own views.
"OK, so if I define what I mean by 'God,' and then logically prove he exists, will that be enough for you?"
Even after centuries of effort, nobody has come up with a watertight logical proof of the existence of God. In spite of this, however, people often feel that they can logically prove that God exists.
Unfortunately, reality is not decided by logic. Even if you could rigorously prove that God exists, it wouldn't actually get you very far. It could be that your logical rules do not always preserve truth -- that your system of logic is flawed. It could be that your premises are wrong. It could even be that reality is not logically consistent. In the end, the only way to find out what is really going on is to observe it. Logic can merely give you an idea where or how to look; and most logical arguments about God don't even perform that task.
Logic is a useful tool for analyzing data and inferring what is going on; but if logic and reality disagree, reality wins.
"Then it seems to me that nothing will ever convince you that God exists."
A clear definition of 'God,' plus some objective and compelling supporting evidence, would be enough to convince many atheists.
The evidence must be objective, though; anecdotal evidence of other people's religious experiences isn't good enough. And strong, compelling evidence is required, because the existence of God is an extraordinary claim -- and extraordinary claims require extraordinary evidence.
"OK, you may think there's a philosophical justification for atheism, but isn't it still a religious belief?"
One of the most common pastimes in philosophical discussion is "the redefinition game." The cynical view of this game is as follows:
Person A begins by making a contentious statement. When person B points out that it can't be true, person A gradually re-defines the words he used in the statement until he arrives at something person B is prepared to accept. He then records the statement, along with the fact that person B has agreed to it, and continues. Eventually A uses the statement as an "agreed fact," but uses his original definitions of all the words in it rather than the obscure redefinitions originally needed to get B to agree to it. Rather than be seen to be apparently inconsistent, B will tend to play along.
The point of this digression is that the answer to the question "Isn't atheism a religious belief?" depends crucially upon what is meant by "religious." "Religion" is generally characterized by belief in a superhuman controlling power -- especially in some sort of God -- and by faith and worship.
(It's worth pointing out in passing that some varieties of Buddhism are not "religion" according to such a definition.)
Atheism is certainly not a belief in any sort of superhuman power, nor is it categorized by worship in any meaningful sense. Widening the definition of "religious" to encompass atheism tends to result in many other aspects of human behavior suddenly becoming classed as "religious" as well -- such as science, politics, and watching TV.
"OK, maybe it's not a religion in the strict sense of the word. But surely belief in atheism (or science) is still just an act of faith, like religion is?"
Firstly, it's not entirely clear that sceptical atheism is something one actually believes in.
Secondly, it is necessary to adopt a number of core beliefs or assumptions to make some sort of sense out of the sensory data we experience. Most atheists try to adopt as few core beliefs as possible; and even those are subject to questioning if experience throws them into doubt.
Science has a number of core assumptions. For example, it is generally assumed that the laws of physics are the same for all observers (or at least, all observers in inertial frames). These are the sort of core assumptions atheists make. If such basic ideas are called "acts of faith," then almost everything we know must be said to be based on acts of faith, and the term loses its meaning.
Faith is more often used to refer to complete, certain belief in something. According to such a definition, atheism and science are certainly not acts of faith. Of course, individual atheists or scientists can be as dogmatic as religious followers when claiming that something is "certain." This is not a general tendency, however; there are many atheists who would be reluctant to state with certainty that the universe exists.
Faith is also used to refer to belief without supporting evidence or proof. Sceptical atheism certainly doesn't fit that definition, as sceptical atheism has no beliefs. Strong atheism is closer, but still doesn't really match, as even the most dogmatic atheist will tend to refer to experimental data (or the lack of it) when asserting that God does not exist.
"If atheism is not religious, surely it's anti-religious?"
It is an unfortunate human tendency to label everyone as either "for" or "against," "friend" or "enemy." The truth is not so clear-cut.
Atheism is the position that runs logically counter to theism; in that sense, it can be said to be "anti-religion." However, when religious believers speak of atheists being "anti-religious" they usually mean that the atheists have some sort of antipathy or hatred towards theists.
This categorization of atheists as hostile towards religion is quite unfair. Atheist attitudes towards theists in fact cover a broad spectrum.
Most atheists take a "live and let live" attitude. Unless questioned, they will not usually mention their atheism, except perhaps to close friends. Of course, this may be in part because atheism is not "socially acceptable" in many countries.
A few atheists are quite anti-religious, and may even try to "convert" others when possible. Historically, such anti-religious atheists have made little impact on society outside the Eastern Bloc countries.
(To digress slightly: the Soviet Union was originally dedicated to separation of church and state, just like the USA. Soviet citizens were legally free to worship as they wished. The institution of "state atheism" came about when Stalin took control of the Soviet Union and tried to destroy the churches in order to gain complete power over the population.)
Some atheists are quite vocal about their beliefs, but only where they see religion encroaching on matters which are not its business -- for example, the government of the USA. Such individuals are usually concerned that church and state should remain separate.
"But if you don't allow religion to have a say in the running of the state, surely that's the same as state atheism?"
The principle of the separation of church and state is that the state shall not legislate concerning matters of religious belief. In particular, it means not only that the state cannot promote one religion at the expense of another, but also that it cannot promote any belief which is religious in nature.
Religions can still have a say in discussion of purely secular matters. For example, religious believers have historically been responsible for encouraging many political reforms. Even today, many organizations campaigning for an increase in spending on foreign aid are founded as religious campaigns. So long as they campaign concerning secular matters, and so long as they do not discriminate on religious grounds, most atheists are quite happy to see them have their say.
"What about prayer in schools? If there's no God, why do you care if people pray?"
Because people who do pray are voters and lawmakers, and tend to do things that those who don't pray can't just ignore. Also, Christian prayer in schools is intimidating to non-Christians, even if they are told that they need not join in. It is particularly bad if the prayer is led by a teacher, or otherwise officially endorsed.
The diversity of religious and nonreligious belief means that it is impossible to formulate a meaningful prayer that will be acceptable to all those present at any public event.
This is one reason why the public school system in the USA is not permitted to endorse particular religious beliefs through official prayer time in schools. Children are, of course, quite free to pray as they wish in their free time; there is no question of trying to prevent prayer from happening in schools.
"You mentioned Christians who campaign for increased foreign aid. What about atheists? Why aren't there any atheist charities or hospitals? Don't atheists object to the religious charities?"
There are many charities without religious purpose that atheists can contribute to. Some atheists contribute to religious charities as well, for the sake of the practical good they do. Some atheists even do voluntary work for charities founded on a theistic basis.
Most atheists seem to feel that atheism isn't worth shouting about in connection with charity. To them, atheism is just a simple, obvious everyday matter, and so is charity. Many feel that it's somewhat cheap, not to say self-righteous, to use simple charity as an excuse to plug a particular set of religious beliefs.
To "weak" atheists, building a hospital to say "I do not believe in God" is a rather strange idea; it's rather like holding a party to say "Today is not my birthday." Why the fuss? Atheism is rarely evangelistic.
"You said atheism isn't anti-religious. But is it perhaps a backlash against one's upbringing, a way of rebelling?"
Perhaps it is, for some. But many people have parents who do not attempt to force any religious (or atheist) ideas upon them, and many of those people choose to call themselves atheists.
It's also doubtless the case that some religious people chose religion as a backlash against an atheist upbringing, as a way of being different. On the other hand, many people choose religion as a way of conforming to the expectations of others.
On the whole, we can't conclude much about whether atheism or religion are backlash or conformism; although in general, people have a tendency to go along with a group rather than act or think independently.
"How do atheists differ from religious people?"
They don't believe in God. That's all there is to it.
Atheists may listen to heavy metal -- backwards, even -- or they may prefer a Verdi Requiem, even if they know the words. They may wear Hawaiian shirts, they may dress all in black, they may even wear orange robes. (Many Buddhists lack a belief in any sort of God.) Some atheists even carry a copy of the Bible around -- for arguing against, of course!
Whoever you are, the chances are you have met several atheists without realizing it. Atheists are usually unexceptional in behavior and appearance.
"Unexceptional? But aren't atheists less moral than religious people?"
That depends. If you define morality as obedience to God, then of course atheists are less moral as they don't obey any God. But usually when one talks of morality, one talks of what is acceptable ("right") and unacceptable ("wrong") behavior within society.
Humans are social animals, and to be maximally successful they must co-operate with each other. This is a good enough reason to discourage most atheists from "anti-social" or "immoral" behavior, purely for the purposes of self-preservation.
Many atheists behave in a "moral" or "compassionate" way simply because they feel a natural tendency to empathize with other humans. So why do they care what happens to others? They don't know, they simply are that way.
Naturally, there are some people who behave "immorally" and try to use atheism to justify their actions. However, there are equally many people who behave "immorally" and then try to use religious beliefs to justify their actions. For example:
"Here is a trustworthy saying that deserves full acceptance: Jesus Christ came into the world to save sinners... But for that very reason, I was shown mercy so that in me... Jesus Christ might display His unlimited patience as an example for those who would believe in him and receive eternal life. Now to the king eternal, immortal, invisible, the only God, be honor and glory forever and ever."
The above quote is from a statement made to the court on February 17th 1992 by Jeffrey Dahmer, the notorious cannibal serial killer of Milwaukee, Wisconsin. It seems that for every atheist mass-murderer, there is a religious mass-murderer. But what of more trivial morality?
A survey conducted by the Roper Organization found that behavior deteriorated after "born again" experiences. While only 4% of respondents said they had driven intoxicated before being "born again," 12% had done so after conversion. Similarly, 5% had used illegal drugs before conversion, 9% after. Two percent admitted to engaging in illicit sex before salvation; 5% after. [Freethought Today, September 1991, p. 12.]
So it seems that at best, religion does not have a monopoly on moral behavior.
Of course, a great many people are converted to (and from) Christianity during adolescence and their early twenties. This is also the time at which people begin to drink and become sexually active. It could be that the above figures merely indicate that Christianity has no effect on moral behavior, or insufficient effect to result in an overall fall in immoral behavior.
"Is there such a thing as atheist morality?"
If you mean "Is there such a thing as morality for atheists?," then the answer is yes, as explained above. Many atheists have ideas about morality which are at least as strong as those held by religious people.
If you mean "Does atheism have a characteristic moral code?," then the answer is no. Atheism by itself does not imply anything much about how a person will behave. Most atheists follow many of the same "moral rules" as theists, but for different reasons. Atheists view morality as something created by humans, according to the way humans feel the world 'ought' to work, rather than seeing it as a set of rules decreed by a supernatural being.
"Then aren't atheists just theists who are denying God?"
A study by the Freedom From Religion Foundation found that over 90% of the atheists who responded became atheists because religion did not work for them. They had found that religious beliefs were fundamentally incompatible with what they observed around them.
Atheists are not unbelievers through ignorance or denial; they are unbelievers through choice. The vast majority of them have spent time studying one or more religions, sometimes in very great depth. They have made a careful and considered decision to reject religious beliefs.
This decision may, of course, be an inevitable consequence of that individual's personality. For a naturally sceptical person, the choice of atheism is often the only one that makes sense, and hence the only choice that person can honestly make.
The word "deny" can be used to mean "fail to accept the truth of." In that sense only, atheists deny the existence of God. They are not "in denial," wilfully ignoring evidence; nor do they necessarily positively assert the nonexistence of God.
"But surely discussing God in this way is a tacit admission that he exists?"
Not at all. People talk about Santa Claus every Christmas; that doesn't mean he climbs down the chimney and leaves us all presents. Players of fantasy games discuss all kinds of strange creatures, from orcs and goblins to titans and minotaurs. They don't exist either.
"But don't atheists want to believe in God?"
Atheists live their lives as though there is nobody watching over them. Many of them have no desire to be watched over, no matter how good-natured the "Big Brother" figure might be.
Some atheists would like to be able to believe in God -- but so what? Should one believe things merely because one wants them to be true? The risks of such an approach should be obvious. Atheists often decide that wanting to believe something is not enough; there must be evidence for the belief.
"But of course atheists see no evidence for the existence of God -- they are unwilling in their souls to see!"
Many, if not most atheists were previously religious. As has been explained above, the vast majority have seriously considered the possibility that God exists. Many atheists have spent time in prayer trying to reach God.
Of course, it is true that some atheists lack an open mind; but assuming that all atheists are biased and insincere is offensive and closed-minded. Comments such as "Of course God is there, you just aren't looking properly" are likely to be viewed as patronizing.
Certainly, if you wish to engage in philosophical debate with atheists it is vital that you give them the benefit of the doubt and assume that they are being sincere if they say that they have searched for God. If you are not willing to believe that they are basically telling the truth, debate is futile.
"Isn't the whole of life completely pointless to an atheist?"
Perhaps it is to some, but still, many atheists live a purposeful life. They decide what they think gives meaning to life, and they pursue those goals. They try to make their lives count, not by wishing for eternal life, but by having an influence on other people who will live on. For example, an atheist may dedicate his life to political reform, in the hope of leaving his mark on history.
It is a natural human tendency to look for "meaning" or "purpose" in random events. However, it is by no means obvious that "life" is the sort of thing that has a "meaning."
To put it another way, not everything which looks like a question is actually a sensible thing to ask. Some atheists believe that asking "What is the meaning of life?" is as silly as asking "What is the meaning of a cup of coffee?." They believe that life has no purpose or meaning, it just is.
Also, if some sort of mystical external force is required to give one's existence a "meaning," surely that makes any hypothetical god's existence meaningless?
"So how do atheists find comfort in time of danger?"
There are many ways of obtaining comfort:
Your family and friends
Food and drink
Music, television, literature, arts and entertainment
Sports or exercise
That may sound like rather an empty and vulnerable way to face danger, but so what? Should individuals believe in things because they are comforting, or should they face reality no matter how harsh it might be?
In the end, it's a decision for the individual concerned. Most atheists are unable to believe something they would not otherwise believe merely because it makes them feel comfortable. They put truth before comfort, and consider that if searching for truth sometimes makes them feel unhappy, that's just hard luck. Often truth hurts.
"Don't atheists worry that they might suddenly be shown to be wrong?"
The short answer is "No, do you?"
Many atheists have been atheists for years. They have encountered many arguments and much supposed evidence for the existence of God, but they have found all of it to be invalid or inconclusive.
Thousands of years of religious belief haven't resulted in any good proof of the existence of God. Atheists therefore tend to feel that they are unlikely to be proved wrong in the immediate future, and they stop worrying about it.
"So why should theists question their beliefs? Don't the same arguments apply?"
No, because the beliefs being questioned are not similar. Weak atheism is the sceptical "default position" to take; it asserts nothing. Strong atheism is a negative belief. Theism is a very strong positive belief.
Atheists sometimes also argue that theists should question their beliefs because of the very real harm they can cause -- not just to the believers, but to everyone else.
"What sort of harm?"
Religion represents a huge financial and work burden on mankind. It's not just a matter of religious believers wasting their money on church buildings; think of all the time and effort spent building churches, praying, and so on. Imagine how that effort could be better spent.
Many theists believe in miracle healing. There have been plenty of instances of ill people being "healed" by a priest, ceasing to take the medicines prescribed to them by doctors, and dying as a result. Some theists have died because they have refused blood transfusions on religious grounds.
It is arguable that the Catholic Church's opposition to birth control -- and condoms in particular -- is increasing the problem of overpopulation in many third-world countries and contributing to the spread of AIDS world-wide.
Religious believers have been known to murder their children rather than allow their children to become atheists or marry someone of a different religion. Religious leaders have been known to justify murder on the grounds of blasphemy.
There have been many religious wars. Even if we accept the argument that religion was not the true cause of those wars, it was still used as an effective justification for them.
"Those weren't real believers. They just claimed to be believers as some sort of excuse."
This is rather like the No True Scotsman fallacy.
What makes a real believer? There are so many One True Religions it's hard to tell. Look at Christianity: there are many competing groups, all convinced that they are the only true Christians. Sometimes they even fight and kill each other. How is an atheist supposed to decide who's a real Christian and who isn't, when even the major Christian churches like the Catholic Church and the Church of England can't decide amongst themselves?
In the end, most atheists take a pragmatic view, and decide that anyone who calls himself a Christian, and uses Christian belief or dogma to justify his actions, should be considered a Christian. Maybe some of those Christians are just perverting Christian teaching for their own ends -- but surely if the Bible can be so readily used to support un-Christian acts it can't be much of a moral code? If the Bible is the word of God, why couldn't he have made it less easy to misinterpret? And how do you know that your beliefs aren't a perversion of what your God intended?
If there is no single unambiguous interpretation of the Bible, then why should an atheist take one interpretation over another just on your say-so? Sorry, but if someone claims that he believes in Jesus and that he murdered others because Jesus and the Bible told him to do so, we must call him a Christian.
"Obviously those extreme sorts of beliefs should be questioned. But since nobody has ever proved that God does not exist, it must be very unlikely that more basic religious beliefs, shared by all faiths, are nonsense."
The commonality of many basic religious beliefs is hardly surprising, if you take the view that religion is a product of society. From that viewpoint, religions have borrowed ideas which contribute to a stable society -- such as respect for authority figures, a prohibition against murder, and so on.
In addition, many common religious themes have been passed on to later religions. For example, it has been suggested that the Ten Commandments of the Old Testament actually have their roots in Hamurabi's code.
The claim that because something hasn't been proved false, it's less likely to be nonsense, does not hold. As was pointed out earlier in this dialogue, positive assertions concerning the existence of entities are inherently much harder to disprove than negative ones. Nobody has ever proved that unicorns don't exist, and there are many stories about them, but that doesn't make it unlikely that they are myths.
It is therefore much more valid to hold a negative assertion by default than it is to hold a positive assertion by default. Of course, "weak" atheists may argue that asserting nothing is better still.
"Well, if atheism's so great, why are there so many theists?"
Unfortunately, the popularity of a belief has little to do with how "correct" it is, or whether it "works"; consider how many people believe in astrology, graphology, and other pseudo-sciences.
Many atheists feel that it is simply a human weakness to want to believe in gods. Certainly in many primitive human societies, religion allows the people to deal with phenomena that they do not adequately understand.
Of course, there's more to religion than that. In the industrialized world, we find people believing in religious explanations of phenomena even when there are perfectly adequate natural explanations. Religion may have started as a means of attempting to explain the world, but nowadays it serves other purposes as well. For instance, for many people religion fulfils a social function, providing a sense of community and belonging.
"But so many cultures have developed religions. Surely that must say something?"
Not really. Most religions are only superficially similar; for example, it's worth remembering that religions such as Buddhism and Taoism lack any sort of concept of God in the Christian sense. In short, there is no consensus amongst religions as to what God actually is. Hence one of the problems you must face if you wish to discuss God with an atheist, is that of defining exactly what you mean by the word.
Also, most religions are quick to denounce competing religions, so it's rather odd to use one religion to try and justify another.
"What about all the famous scientists and philosophers who have concluded that God exists?"
Firstly, note that surveys typically find that around 40% of scientists believe in god; so believers are in the minority. (The most recent survey was by Edward J. Larson and Larry Witham, was carried out in 1996, and was reported in the journal "Nature.")
For every scientist or philosopher who believes in a god, there is one who does not. Besides, as has already been pointed out, the truth of a belief is not determined by how many people believe it. Also, it is important to realize that atheists do not view famous scientists or philosophers in the same way that theists view their religious leaders.
A famous scientist is only human; she may be an expert in some fields, but when she talks about other matters her words carry no special weight. Many respected scientists have made themselves look foolish by speaking on subjects which lie outside their fields of expertise.
Also, note that even famous scientists' views are treated with scepticism by the scientific community. Acknowledged experts in a particular field must still provide evidence for their theories; science relies on reproducible, independently confirmed results. New theories which are incompatible with a large body of existing scientific knowledge will be subject to especially close scrutiny; but if the work is sound and the experimental data reproducible, the new theories will displace the old.
For instance, both special relativity and quantum mechanics were highly controversial, and required that a lot of existing scientific theory be thrown out. Yet both were relatively quickly accepted after extensive experiments proved their correctness. Pseudo-scientific theories such as creationism are rejected not because they are controversial, but because they simply do not stand up to basic scientific scrutiny. (For futher information, see the FAQs for http://www.talkorigins.org/.)
The Constructing a Logical Argument document has more to say about scientific verification and proof by authority.
"So are you really saying that widespread belief in religion indicates nothing?"
Not entirely. It certainly indicates that the religion in question has properties which have helped it to spread so far.
The theory of memetics talks of "memes" -- sets of ideas which can propagate themselves between human minds, by analogy with genes. Some atheists view religions as sets of particularly successful parasitic memes, which spread by encouraging their hosts to convert others. Some memes avoid destruction by discouraging believers from questioning doctrine, or by using peer pressure to keep one-time believers from admitting that they were mistaken. Some religious memes even encourage their hosts to destroy hosts controlled by other memes.
Of course, in the memetic view there is no particular virtue associated with successful propagation of a meme. Religion is not a good thing because of the number of people who believe it, any more than a disease is a good thing because of the number of people who have caught it.
The memetic approach has little to say about the truth of the information in the memes, however.
"Even if religion is not entirely true, at least it puts across important messages. What are the fundamental messages of atheism?"
There are many important ideas atheists promote. The following are just a few of them; don't be surprised to see ideas which are also present in some religions.
There is more to moral behavior than mindlessly following rules.
Be especially sceptical of positive claims.
If you want your life to have some sort of meaning, it's up to you to find it.
Search for what is true, even if it makes you uncomfortable.
Make the most of your life, as it's probably the only one you'll have.
It's no good relying on some external power to change you; you must change yourself.
Just because something's popular doesn't mean it's good.
If you must assume something, assume something easy to test.
Don't believe things just because you want them to be true.
And finally (and most importantly):
All beliefs should be open to question.