Arguments that don't make it
I recently had a conversation with a friend about religious beliefs. This friend brought up some of the reasons why he believed his religion was true. I didn't think they were good enough reasons to justify belief in a god, and since I had asked for reasons before, I thought I'd list some of the more common arguments and why I don't buy them. Note that this friend did not make all of these arguments, and I did not make all these responses.
Granted, these aren't new arguments, or new responses, but I thought I'd list them here for fun.
1) The universe needs/had a cause, and that cause is God.
There are several problems with this one.
First, it is far from certain that "the universe had a cause" even makes sense, much less is proven as a fact. If time is a property of the universe, it doesn't make sense to ask what caused it, since "caused" implies a "before" and you can't have a "before" without time. It seems to me that one alternative is that the universe itself is uncaused, and/or could have existed forever in some form or another.
Second, even if you could unequivocally say the universe had a cause outside of itself, couldn't the "first cause" (if it is needed) be something else besides something with a "god" label? Some unconscious process or force? Some pre-existing meta-verse, some quantum event thingamabob, or some other made-up sciency-sounding thing? The point is there's no justification for assuming "god".
Third, even if you could show this might-be-needed thing must have been intelligent, why call it a "god" of any kind, much less a very specific uppercased "God"? Sure, it is a creator, but how does the thought that the universe needs an intelligent creator imply that the creator gets angry if I have sex before I'm married? It can't. How could it show that the creator isn't the equivalent of a metaphysical child with a "create your own universe chemistry set"? It can't. The point is there's no justification for assuming "God" or "Allah" or "Vishnu".
Finally, if we say the universe does need a cause, why does the creator of the universe not need a cause? After all, we just spent all this time saying "everything needs a cause", does it make sense now to say, "oh, but not god". The most popular answer to this is that the creator does not need a cause because it/she/he exists outside of time, or is not constrained by time. My first response to this is "That's very convenient". It seems like we've just declared for convenience that this thing doesn't need a cause.
If we can declare that something doesn't need a cause, wouldn't it be much simpler to just say that uncaused "thing" is the universe? After all, time is a part of the universe, not the other way around. Can't we just declare that the universe contains time, and therefore is not constrained by it? Using that particular chain of unproven thought, the universe could be uncaused/self-caused after all.
Do I believe that? I don't know if it's true or not; I'm merely pointing out that the argument is not nearly as cut and dried as the god proponents make it seem.
Does the universe need a cause? I don't know, and nobody else does either. Does that may-be-needed cause meet somebody's definition of "god"? I don't see any reason to think so.
2) If the believers are right, they have everything to gain, but if they are wrong, they have nothing to lose.
This is Pascal's wager: If the atheist is right, she gains nothing because there's no afterlife, but if she is wrong, she'll lose everything and burn in hell. If the believer is right, he'll gain eternal life, but if he is wrong, there's no harm done and he'll simply cease to exist. Therefore, it is better to believe.
As usual, there are several flaws in this argument.
The greatest difficulty is that the wager isn't a binary choice: to believe or not to believe. Most people come with a pre-existing religion and therefore think the choice is simple, but the happenstance of a person's religion doesn't mean the choice is a simple yes or no. You also have to decide what to believe.
Over the centuries, there have been thousands of religions and thousands of incompatible belief systems. Which one is true? If the Muslims are right, most people in the US are screwed, and vice versa. If the Hindus are right, we'll all be back as roaches for failing to properly prepare ourselves. If the Heaven's Gaters were right, everyone but those 38 original followers are screwed. You may think these beliefs are silly, but they think the same about yours, and I, as an outsider, see no way to say one is less silly than the other. You might take a new-age PC stance and say "the real god doesn't care about your religion", but that's really just one more incompatible belief and could be just as wrong if the real god really does care and sends your love-everyone butt to hell.
So, by choosing Christianity, or Islam, or Shinto, or Hindu, or one of the thousands and thousands of other beliefs, you are taking the chance of pissing off the "real god", and have plenty to lose if you're wrong. So in this wager, you're in exactly the same position as the lowly atheist: screwed in the event you're wrong.
Second, even if it was a binary decision, it is wrong that there is nothing to lose. In this life, we all make choices based on our beliefs. If you believe your god doesn't like alcohol or pork, you can't have a beer or bratwurst with your meal. If you believe your god wants to be worshipped, you'll go to church on Sunday, pray five times a day, or sing crappy rock music. These might not seem like much, but if you're wrong you did a lot of things for nothing, and possibly missed out on any number of experiences.
More troubling: If you believe your god created the universe in 6 days, you'll try to change science classes. If you believe your god thinks you are the chosen people, you'll be racist or uphold slavery. If you believe your god likes men better, you'll prevent women from voting or holding property, or cut off their clitorises.
There are very real costs if the believer is wrong. Your particular religion might not contain the examples above (or perhaps it got rid of them recently), but I'm sure you'd live your life differently if you did not have your religion. There are costs.
Third, what kind of self-respecting god would like it if you believed in it and worshipped it simply because you're hedging your bets? I'm certain that if the god of the old testament is real, you're screwed if you're merely betting it's right.
3) Just like I know a found clock/watch was created, I know the universe/life was created.
This is the classic watchmaker argument put forth hundreds of years ago. It's still invalid.
This is a complex one, because it contains so many implications.
The first is that people are somehow able to recognize when something is created. I think this is false. In the 1950s, radio astronomers began detecting very regular radio pulses from space. Many people believed it was not possible the signals were natural, and thought they were alien transmissions. They turned out to be a naturally occurring product of things called quasars. These people's "creator detectors" were falsely activated. Another example would be the Giants Causeway.
When people look into the sky and see a circular orbit, or look at an animal and see a complex organism, their "creator detectors" might be tripped, but that doesn't mean these things were, in fact, designed.
It turns out very complex things can arise from very simple rules. Add gravity plus a pile of atoms and you get complex orbits, neat ellipses and nearly spherical planets. No one needs to create the orbits and the planets, they come about naturally because of the few simple rules of the universe. You could say "God created the rules", but that is a different argument than saying "God created the planets and the orbits".
In the same way, very complex organisms can come about because of the simple rules of reproduction, mutation, and selection. (I won't give another full explanation of evolution. Many people have explained it before in many places (here's mine). Suffice to say that evolution is as near a fact as something can be in science.)
Second, we can sometimes recognize human-created objects when we see them because we are familiar with humans and their capabilities, and we know what kinds of things humans make, not because of some inherit property of all designed objects. We know lots of things about humans, but we know nothing about gods. How could we possibly recognize their creations?
Third, I can watch an animal grow from an embryo to adult, and there doesn't appear to be any creator involved. Every day, more and more about the process of reproduction is discovered, and a creator doesn't seem to play a part in it. You can say that god created life itself, or even that god directs evolution, but clearly the direct analogy of a manufactured clock to a growing animal is off. Clocks do not reproduce at all, much less have reproduction with modification and selection.
Fourth, once again, even if you could show life was created and therefore had a creator, why assume "gods" at all, much less "God", "Brahma", etc? It could be our metaphysical baby genius, or aliens with a planet seeding hobby, etc. The evidence -the existence of the universe and life- doesn't justify the conclusion -the existence of one or more beings with superpowers and an intense interest in people's sex lives and eating habits, or souls, spirits, angels, etc.
These arguments, like all arguments for the existence of gods I've ever heard, are not intended for the non-believers; they are for the consumption of those who already have a belief system. They support all religious theories equally, and not very well.
Also, although I've given counter-explanations for some of the things above, that doesn't mean I need to. I don't have to explain where the universe came from in order to say there's no evidence for gods creating the universe. "I don't know" is a perfectly valid answer. Likewise, evolution doesn't have to be true in order for me to say there's no reason to believe in a creator of life. "I don't know" is a more honest answer.
If you discover a broken mirror on the floor and tell me "George broke it", it is up to you to show why you think it was George. I don't need to explain any other ways the mirror could have come to be that way. I can say "I don't know how it happened, and you don't either."
To be continued, I'm sure.