I just wanted to explain my beliefs as a non-theist, particularly to see if anybody has any constructive criticism or if there are any holes in my arguments:
What is non-theism?
Essentially a non-theist is someone who does not have faith in a personal God, in non-theist philosophy, God's existence or inexistence is irrelevant.
For simplicity's sake, when I say God here, I mean an intelligent, supernatural entity (or group of such entities) which created the universe and by supernatural, I mean not bound by the laws of physics as we understand them, particularly cause and effect.
Why non-theism?
First off, there is no evidence (to my knowledge) that theists are more moral people or that they are less likely to do anything society traditionally views as "wrong" or "evil". Thus God is unecessary for a healthy human society to exist, moral behaviour is dependent on individuals, not upon absolutes imposed by a divine entity. Hence unless God can be shown to have a useful function, such an entity is irrelevant.
So outside of morality, what function is God claimed to perform? The first answer that comes to my mind is the idea of an afterlife. Leaving aside the question of whether eternal consciousness is any better than oblivion (I'm not so sure that it is), we are innevitably led to the idea of "Pascal's Wager". Besides the fact that the odds of picking the "right religion" are incredibly slim, even if there was only one possible true religion with a God who punishes you for picking the wrong one, I personally could not bring myself to worship such an entity. How can one possibly spend eternity in willing service to a tyrant? I'd go insane (assuming that such a God would even allow me that much free will). Hence the afterlife/Pascal's Wager is not a valid reason to be a theist
The above two paragraphs cover my thoughts on faith in a personal God. The next two paragraphs will adress the argument for the existence of an intelligent creator God.
Next, the "first cause" argument, this classical argument runs thus: "everything requires a cause, hence there must be a first cause, this cause would have to be outside of the laws of physics as we understand them (and hence can be described as a "God"), or it too would require a cause". The error in this logic is to assume that the universe is temporally finite, that is to say, that the universe doesn't stretch into an infinite expanse of time. Scientifically speaking we can't assume either way. Even if the first cause argument were not fallacious, it would tell us nothing of the nature of such a God and hence we still wouldn't know which God to worship.
Similar to the first cause argument is the "divine watchmaker" argument, the argument that the complexity of the universe lends itself to intelligent creation. The example often used is a watch in a desert with no footprints around for miles. However, this is merely anthropomorphising, we know that a watch cannot make itself and thus has to be made, we don't know either way whether a universe has to be made. After all, snowflakes are incredibly complex, but they are no individually designed by an intelligent entity, despite their subjective beauty and complexity.
In conclusion, God is irrelevant to humanity, both morally and logically, we just can't know whether God exists or not, so why worry about it?
Please tell me if I've missed anything.