The argument from incoherence is a sound argument for the non-existence of God.

Thank you, KeytarHero, for your reply.PREMISE 1: ANYTHING WITH INCOHERENT ATTRIBUTES CANNOT EXISTThis is basically conceded by both me and my opponent. My opponent, and I, both agree that "entities that are logically incoherent cannot exist." PREMISE 2: GOD HAS INCOHERENT ATTRIBUTES I have given two examples of contradictory attributes: all-knowing vs. all-powerful; and free-will-vs.-all knowing. Omniscient vs. OmnipotentMy opponent concedes that God is both all-knowing and all-powerful. I too concede that God, as a MGB, has all great making properties, and has them to their maximal extent. My opponent states:It is true that God knows the future. It is also true that God can change the future, if he wishes. This is not contradictory. This is because God knows all possible futures. For example, take the case of Jonah and the Ninevites. Jonah was instructed by God to go to Ninevah to encourage them to repent of their sins, for they were going to be destroyed due to their wickedness in forty days (Jonah 3:4). God knew this was going to happen, and left alone this would have happened. However, God is also a merciful God. Jonah (eventually) preached to the people of Ninevah, and they repented of their wickedness. Therefore, God had mercy on them and did not destroy them. God knew that He was going to destroy the city if they did not repent, but God being a merciful God spared their city because of their repentance. This can also be seen in the ultimate destination of all mankind. Everyone is on their way to Hell, but they can change their destination if they repent and trust in Jesus for their salvation. God doesn't just know the future, He knows all possible futures.It appears my opponent's way to "resolve" this contradiction is to point out that God knows all possible futures to which I concede. The problem lies not only in the fact that God knows all POSSIBLE futures; but that God, by necessity, also knows the possible future that will happen inevitably. My opponent concedes this point by stating that, "[T]here are some things that can't change. God knew that He was going to create mankind, that humans would sin, and he would eventually have to send Jesus to save us from their sins. These were decreed by God and could not be changed." However, this contradicts free will. For example, if God didn't want to send Jesus, then he had no choice and thus no free will of the concept. Moreover, my opponent concedes that there are things that God cannot change. This means that prayer is pointless becaues God knows the future, he knows all possible futures, and he knows the future that is inevitably going to occur; hence, prayer cannot change the outcome of any situation.Regarding my analogy, con states that there is one way I can change the outcome -- namely, that I could assassinate him. However, for Obama to win the election that will inevitably occur, it is also required that Obama is alive during the election; hence, I could not assassinate him. (Note, although I dislike Obama, I too will never advocate assassination of our President nor would I ever do such a thing). Free will vs. All-Knowing. Con states that it is not impossible for an omniscient being to be free. God knows what actions he will do, but he also knows possible actions that he would do. However, this is incoherent for the same reasons listed above. Although he knows POSSIBLE actions, he knows the inevitable future of his action and cannot in any way change the direction that his action is going to lead to. For example, a million years before the Creation of the Universe, God had no way of stopping the inevitable Creation of the universe and the "fact" that he would have to send Jesus Christ to save mankind. This also overlooks the simple fact that an omniscient being would know a particular action will occur, even though a less desirable action may occur. For example, even though God told Jonah he will destroy Ninevah in forty days (due to their wickedness), he definitely knew that they would repent and that he would spare them, before the events even occurred. So in that respect, he does know exactly what will happen even though there is the possibility of different outcomes.Regarding this statement, this is incoherent. My opponent states that God knows exactly what will happen, even though there is the possibility of different outcomes. However, this begs the question -- doesn't God know the exact outcome that is going to happen? If we say that God knows everything, we must also say that he knows all possible outcomes and the outcome that is inevitably going to occur -- hence, God cannot also change the outcome of any event. God is powerless in that regard. Simply knowing what actions will occur does not mean that God wasn't free to do otherwise. For example, God could have just as easily not created the universe. The fact that he knew ahead of time that he would created it does not mean he wasn't free to create it. It just meant he knew what he would do ahead of time. Just like if you know you're going to go to the mall next Saturday, you are still free to do otherwise. You could have any number of good reasons for not going, or you may just not feel like going that day. The difference is that God, being omniscient, knows for sure what will happen and it won't change (or if it will change, God knows that, too).God could have just as easily not created the universe; however, the fact that he knew ahead of time prevented him from not creating it. Just like if you know for all certainty that you are not going to the mall next Saturday, you have no free choice and no power to do otherwise. Conclusion"[T]he characteristics of God as supplied by Christian theologians are nothing more than meaningless and contradictory concepts wrapped in theological garb." (http://rejectionofpascalswager.net...;)