Consider the following argument (I shall call it ‘the atheist's argument’) for the non-existence of God:
(1) Some men are morally reprehensible for failing to perform certain actions, e.g. actions of abolishing suffering which is destructive of character.
(2) Concentrate, for simplicity, just on actions of this latter sort. If there is an omnipotent and omniscient being, then he, too, fails to perform actions of this sort, and, hence, he is also morally reprehensible unless some such difference obtains between him and the men mentioned in (1) (call them ‘M’) as his being unable to abolish this suffering, while M is able to abolish it, or his not knowing that this suffering is in fact destructive of character, while M does know this.
(3) But being omnipotent and omniscient is incompatible with any such difference obtaining. (For example, being omnipotent is incompatible with being unable to abolish the suffering under discussion and being omniscient is incompatible with failing to know that a given instance of suffering which is destructive of character does in fact have that property.)