I know, aren’t you just sick of those?
My own reasoning goes as follows:
If a god exists, no one has shown it. Therefore I live in skepticism until such a time.
I’ve never seen evidence for any of the following assertions, that A) the existence of the natural world predicates the existence of a supernatural world, B) that a god, if it does exist, is necessarily benevolent, omnipotent, et cetera, or C) that holy books and holy men have anything valuable to say concerning god’s existence, whether or not such a being exists.
A) Every time a religion sets the limits of observable inquiry, we seem to break those limits. After repeated such offenses, religion lacks the credibility to make claims of these kinds, and should stop. The “supernatural world” is simply a convenient mnemonic for “things science hasn’t yet figured out”. It’s an easy way to claim to know what you’re talking about when you really don’t.
B) It does not necessarily follow that a god, if it does exist, is omnipotent, omniscient, and benevolent.
For example, assuming a god does exist, how do we know that he is omnipotent? Maybe he only knows how to initiate big bangs, and nothing else. It doesn’t necessarily follow that the creator of the universe has unlimited power. Maybe he just has that specific power, the power to create universes. After all, there exist no credible documentations of miracles, ghosts, visions, creation events, or any other such thing. Everything we observe appears to function naturally, without any intervention.
Assuming an omnipotent god does exist, how do we know that he is benevolent? He could intervene in world affairs and then just erase everyone’s memory, could he not? He could be manipulating us all like dolls at all times, while giving us the illusion of consciousness. He could be doing any number of things which contradict his supposed benevolence. And it doesn’t say much, either, that the world is full of pestilence, inequity, iniquity, and war. It’s easy to ask the question, “If I were omnipotent, could I do a better job?” I could. Especially if I had this god with which to judge myself against.
At the heart of it, God’s benevolence, or omnipotence, or omniscience, are assumptions religious individuals make because they jive with their specific religious dogma, not because the idea of a god necessitates them.
The holy books contradict one another and themselves. The prophets and priests contradict one another and themselves. They have no credibility whatsoever. They rely on inherited authority, not earned authority.
I have more philosophical criticisms of the idea of God, but these are just the obvious ones I sort of frame my disbelief around.