One of the assumed arguments against the existence of what is referred to by God is an emotionally based one which cites the existence of evil or dreadful occurrences as said proofs - for instance the Nazi Holocaust or even some sinister phenomenon within the natural world. What 'God' stands for or signifies within this sphere of argument is an Ultimate Reality which is incarnate as absolute goodness, and because of its ultimate nature, its ultimate and undoubted triumph over evil.
The argument against God in this usage can go more or less that the level of evil in whatever instance used is so awful that ultimate truth, goodness, or God, cannot exist or else it would not have allowed such evil to prevail.
It is not to belittle the intensity of the pain that may lead to this philosophical reaction of God's absence but it should still be remembered that language must be examined in its own terms; the intellect must be true to itself and its forms; otherwise driven by these powerful even hysterical emotional needs and yearnings, intellect can be made to furnish and uphold very doubtful and dangerous ideas like virulent forms of state nationalism and its subsequent manifestations, from war to concentration camps.
And so back to the matter of this idea of the absence of the existence of absolute goodness and truth due to whatever temporal triumph of evil - and thankfully once true to language it can be resolved very quickly.
The very use of the word 'evil' and its usage is to inescapably accept that it exists within the framework or greater reality of 'Good.' Evil or some awful occurrence can be experienced as evil or awful only because of their being at odds with the goodness which the self feels and knows to be truth.
This all relates quite closely to a post Perversion as Truth, particuarly:
The very notion of perversion being 'true' is linguistically, and tautologically so, perverse, nonsensical. The idea of the language term "perversion" necessitates the idea of healthiness, truth, to which this perversion is contrary. It cannot exist autonomously without this standard to offset itself. It exists in relation to truth, which it is in defiance of, in perverse relation to.
And identically we can substitute evil for perversion. 'Evil' can only exist as a false domain within the framework of 'Goodness.' Something can only be wrong in the event of something else being right. For instance, 2+2=5 is wrong because of there being a right answer. If there was no right, there would be no wrong. And just so with the emotional or ethical sphere.