give me a rational reason to substantiate your basis for being an atheist

I hope it will be very productive . I hope after this my opponent will see that my repetitive arguments are very valid cases against the existence of both a theist and a deist type of god. So on that note, lets begin. I will be starting out with four contentions and might add more if the moment calls for I just ask that my opponent refrain from posting new arguments in the final round because that would be just plain unfair. Contention 1: Lack of Extraordinary EvidenceI will begin with a fairly well-known quote by Carl Sagan:"Extraordinary claims require extraordinary evidence" [1]. With that said, I will now get to the point. There is no real nor extraordinary evidence for the existence of God. If there be any that I am not aware of then my opponent has the burden to present it. My opponent has the Burden of proof because it is always left to those claiming something exists to prove that the thing to which they referring to (in this case God) exists. For example: If I were to come up to my opponent and say to him that had seen a Unicorn and that they do exist, my opponent would have no reason to believe me unless I either show the Unicorn or the evidence that says the Unicorn exists. It would not be my opponent who had to prove that the unicorn didn't exist, it would be all up to me to prove that it does exist. The same that would apply to there, also applies to here. Contention 2: The Impossibility of an AfterlifeMy next contention really just speaks for itself. I will prove the impossibly of an afterlife. For this I will do a syllogism:P1: Studies have shown that there exists a strong connection between mental events and brain events that neither can exist without the other. P2: In a afterlife, there would occur mental events without brain events. C: Therefore, An afterlife is impossible. Now, I know what your thinking, if there is a soul then it doesn't require a brain to function. However, this is proven false by my first premise. There are certain injuries to the brain that if happened a person would have no mental state (they would be brain dead). While others destroy various mental capabilities. Which capability is destroyed is determined by which part of the brain was effected. So it is clear that we do not have a soul to carry out mental capabilities further then the brain we have now [2]. Contention 3: Omnipotence is ImpossibleFor my third contention I contend that omnipotence (or the state of being all-powerful) is in fact logically impossible. I will prove this by using a very old and well known method for do this. It is known as the Paradox of the Stone , and it goes like this:If God is all-powerful, then he could create a stone that is so heavy that he could not lift it. However, if he does then he proves that he is not all-powerful. Since omnipotence is a key aspect of God, and since omnipotence is a logical impossibly. Then God is impossible. Contention 4: Argument from EvilI will begin this with a syllogism:P1: If God exists, then there would be no suffering in the world. P2: Suffering existsC: Therefore, God does not. The god of the Bible is supposed to be all-powerful, all-knowing, and also all-loving. However, an all-loving god would do something to prevent suffering. But we see suffering everyday from the holocaust, to 9/11, to the AIDs epidemic in Haiti, And the fact that he is both all-powerful and all-knowing leaves him without an excuse. Therefore, from what the evidence points to, God does not exist. I will add another contention in the next round, unless my opponent forfeits (I hope not). But as for now, I will now await my opponent's response. Thank You. Sources[1]. http://en.wikipedia.org.........[2]http://www.infidels.org.........