Is God willing to prevent evil, but not able?
Then he is not omnipotent.
Is he able, but not willing?
Then he is malevolent.
Is he both able, and willing?
Then whence cometh evil?
Is he neither able nor willing?
Then why call him God.
Often theists like to brush off the burden of proof or to try place it onto those who simply don’t believe. Of course most people realise the absurdity of asking someone to disprove the existence of an item or being they don’t believe in.
We’ve all heard the argument that “you can’t prove god doesn’t exist” and it is technically correct, we can’t prove a deistic god doesn’t exist, in much the same way that we can’t prove an invisible unicorn doesn’t live on Pluto. To conclusively disprove a generic claim like a undefined god, or the invisible unicorn on Pluto, one would have to posses the ability to observe every part of the universe simultaneously. And that is obviously not an ability we have, so disproving generic claims is not possible. However this becomes a completely different situation when traits are attributed to the target of the claim, i.e. god, as most theists are want to do.
Once we begin to attribute traits to something, we then have something to start disproving. As humans we are the ones who define our language and therefore we define what these traits actually mean. And because they have definitions we can show if they could possibly apply to a god.
Several of the traits applied by believers to their particular version of a god disprove that god, or at least show that the existence of a god is extremely unlikely.
Many people will both claim that everything must have a creator and that God has always existed. These claims are in direct conflict with each other and if the first is true then God must have been created by something. However if it isn’t true, and God has always existed or came from nothing, this can be used to explain the existence of the universe in the same way it has been used to explain God. This doesn’t disprove a god, but it does make one unnecessary.
Strictly speaking the idea that a being could be truly omnipotent, in the way many people think of it, is flawed in so much as paradoxes(such as creating a rock so heavy even God can’t move it) make it impossible. However if we restrict omnipotent to meaning “possessing the most power logically possible” then theoretically an omnipotent god could exist, at least until it is attributed other traits.
Omniscience is something that can not truly exist, to know every piece of information that exists is impossible as if there may always exist a piece of information you don’t know about. And if you don’t know something, even if you’re not aware that you don’t know it, you are not truly omniscient.
The pain and suffering that occurs on a daily basis, not to mention the idea of hell, prove that if a god exists he is not omnibenevolent.
These are just a few of the traits often attributed to a god and they help to build quite a good case against the existence of that particular flavour of God. We may not be able to disprove a deistic god but we can say quite easily that an all knowing, all powerful, all loving god certainly doesn’t exist.