Short answer: For the same reason I don’t believe in Santa Claus, the Tooth Fairy or the Easter Bunny, or anything else that doesn’t exist.
Long answer: I don’t know what I don’t know. I see that mankind had 3 big questions -
1) Where do we come from?
2) Why are we here?
3) What happens when we die?
Any approach to understanding life will attempt to answer those questions, and essentially, we have as humans developed two major approaches to understanding life….one is faith and one is science.
Science is based on observations. The behavior of everything in the world is observed and patterns are detected. Based on these observations, one makes an educated guess about how something works. If that guess is correct, one would be able to predict what would happen under certain circumstances. So, one tests if the guess is correct by constructing experiments. If this experiment works, the guess if formed into a hypothesis. That hypothesis is then tested over and over and over again by thousands of people all over the world, and when one can consistently demonstrate that this hypothesis can correctly predict an outcome, then it becomes a theory. And basically, it never really goes farther than that. Many people regard gravity as a fact, but it is a theory…it is a theory that is accepted by everyone, but it is still a theory. In much the same way, evolution is a theory…it is no longer a hypothesis, the theory of evolution has been demonstrated repeatedly and consistently by people around the world for many years to be able to consistently and accurately predict occurrences. It is accepted by almost every scientist, pretty much at the same levels as gravity. In short, we know, we do not just think that people evolved from lower life forms. But of course, it is still a theory, we don’t know what we don’t know, because perhaps there is something about the universe that we don’t yet understand which would explain these results and paint them in a new light.
Faith on the other hand, can be based in observation, but the similarities to science end there. Faith is basically hypothesis that can not be tested. One must accept this hypothesis as fact without the evidence provided by science. No one can develop experiments to test faith, experiments that can be replicated throughout the world where all studying it come to the same conclusion. In fact, unlike science, in different parts of the world, the prevailing hypotheses are completely different. We have different religions, we do not have different sciences. Each religion shares with science the commonality of attempting to answer the 3 big questions, but rather than arriving at those answers through a systematic method, each relies on a moral certitude…it is so, because I believe it is so.
And all the world’s religions are not compatible, each major religion has deep philosophical disagreements about the big questions. And unfortunately, our modern religions do not seem to have any differentiation between themselves and the religions of the past in which no one has any faith these days. Indeed, historically, one can look at religion as having held the same purpose…to explain things…that it holds today. In the not too distant past, people believed that the sun and the moon and the stars were Gods. Today we know that they are not, an no one believes these things anymore. However, what was the purpose of this worship? These hypotheses were certainly developed through observation….the sun gives us life, therefore it must be a God. But there was no way to test that….when science did become able to test that hypothesis, it was quickly dispelled, though faith is deeply rooted and inflexible, and any challenges to it are considered heresy. This is because the very nature of faith is to believe without question.
So, when Galileo just 400 years ago proved that the Earth revolved around the Sun and not the other way around, he was forced to recant his views (even though they were really observations of fact and not “views”) because they conflicted with the views of the church (which really WERE views, which had no basis in observation or evidence). Indeed, the Catholic church is so resistant to change that it took them until 1990 to apologize to long dead Galileo. Today, we see parallels throughout history of religion forming a hypothesis out of nothing other than an inherent need to understand what one observes and being proven incorrect.
At the current time, science offers us the following explanations:
1) We evolved from lower species, and we are still working out the details about how the universe came to be, but we know that man is a product of millions of years of evolution from lower life forms, and that this life is a product of the basic building blocks of life…heat, water, energy. We don’t have all the answers, but we’re working on it, and we have a pretty good idea, and certainly know enough to know that life is a natural process.
2) If there is an ultimate “purpose” we have not yet found it, but we do know that life is insistent, life wants to survive and adapt…we can find life forms in the most punishing environments, and we believe we will find life in space as well. Life is just something that occurs in nature, and as part of the natural process, life will become more and more adaptable, intelligent and capable. Perhaps our purpose is to find out the answers to these 3 questions (or now 2).
3) We being comprised of organic material cease to function and return to the earth. If there is any other component to consciousness other than natural brain chemistry, we have yet to find it, but we’re sure looking.
So, where does that leave us? Well, for me, I realize that science can not provide all the answers. But having said that, I don’t think a wild guess can either, and I see no evidence to suggest that any religion past or present is anything other than a wild guess. The only support for any religion is faith, it is a self-fulfilling venture. And frankly, it is also self-protecting, one is not only promised the answers for having faith, but one is also promised great rewards far exceeding anything imaginable in life for having faith, but is also threatened with great detriment far exceeding any imaginable pain for not having faith. Religion protects itself by scaring its followers into not asking questions, because as soon as one asks questions that religion can not answer, religion loses credibility.
Now having said all that, I don’t know what I don’t know. Could there be some greater intelligence that set this process in place? Absolutely! It would be arrogant for me to simply say that even the seemingly craziest religious theory is just wrong, because as much as they can not prove that they are right, I can not prove that they are wrong. Unless and until science can somehow provide all the answers to the great questions conclusively and to the exclusion of any other theories to the contrary, religion will always exist, and no one will ever be able to say 100% beyond the shadow of a doubt that ANY religion has it ALL wrong. As long as there are answers to be discovered, we have no idea what those answers may be, and so we can not discount anything entirely no matter how ridiculous it may seem unless we can prove something that ultimately makes it impossible to believe.
A great example is the idea that man is only 6,000 years old and came into existence with the Earth and dinosaurs. It is established beyond any reasonable doubt that this is incorrect. However, could a higher intelligence have planted evidence to purposely throw us off the track…well, how can I say no? Not likely, but not something that can be proven to be fallacious. But I prefer to deal in a logical world. I tend to see that most theories pulled out of thin air tend to be wrong.
So, I don’t know if that makes me an atheist, or an agnostic or what? On one hand, I absolutely do not believe in any God. On the other, I can not discount the possibility that a God or even multiple Gods DO exist. So, it’s hard for me to say I “don’t believe” in God when I acknowledge the possibility, but I can not say I “doubt” the existence of God when I don’t actively believe in one but simply have doubts. Nonetheless, there is no evidence that any religion is more than a wild guess, and therefore, I have to use logic and say that I don’t believe in God, because I have zero evidence of His existence, but I have scads of evidence in things that conflict with a belief in him.