The Apostle Paul says that all men have knowledge of God. So if a person has propositional knowledge at a point in time, then that person has knowledge of God. But either not all men have knowledge of God because some people believe that they do not have knowledge of God due to a defeater, which is a reason that they have to not to believe something, and one cannot know what they do not believe, or knowledge of God cannot be reached. Therefore, not all men know that God exist.
If a person claims to not know who God is, then they claim that they understand who God is and that he does not exist. But from their understanding of who God is, it is possible to show that God exists. They understand that God is a necessary being, so that they understand that he must exist, but they believe that he does not exist anyway. So if they know that God exists, they cannot disbelieve in God, since they have knowledge of him.
If they have both knowledge of God and a reason that God does not exist, then they believe a contradiction. This contradiction defeats the proposition that all men have knowledge of God. If the non-believer has a defeater for his belief in God, then he has a reason why God does not exist. A reason to disbelieve in God is assented to, rather than the belief that God exists. So since a non-believer believes that there is a reason to not believe in God, then not all men believe in God.
Perhaps the non-believer is lying when he says that he has a reason to not believe in God, since if he had a reason to not believe in God, then he would be able to give his reason. But once he gives a reason why God does not exist, then he is giving a reason why a necessary being does not exist. But this is impossible, since a necessary being must exist.
AMR
If a person claims to not know who God is, then they claim that they understand who God is and that he does not exist. But from their understanding of who God is, it is possible to show that God exists. They understand that God is a necessary being, so that they understand that he must exist, but they believe that he does not exist anyway. So if they know that God exists, they cannot disbelieve in God, since they have knowledge of him.
If they have both knowledge of God and a reason that God does not exist, then they believe a contradiction. This contradiction defeats the proposition that all men have knowledge of God. If the non-believer has a defeater for his belief in God, then he has a reason why God does not exist. A reason to disbelieve in God is assented to, rather than the belief that God exists. So since a non-believer believes that there is a reason to not believe in God, then not all men believe in God.
Perhaps the non-believer is lying when he says that he has a reason to not believe in God, since if he had a reason to not believe in God, then he would be able to give his reason. But once he gives a reason why God does not exist, then he is giving a reason why a necessary being does not exist. But this is impossible, since a necessary being must exist.
AMR