1. God does not exist because theists can only make unsubstantiated assertions and flawed syllogisms to “prove” its existence.
2. Because if he did, I would have felt him in my heart by now.
3. Our observations and understandings of reality can all be explained without once ever referring to the existence of a non-physical divine being.
4. Properly critical examination of the evidence will invariably require a rational human to conclude that while there may possibly be a god, there is none-the-less no reason to conclude that there is.
5. Internal feelings are no way prove external realities.
6. The arguments for god’s existence (particularly the “gods currently worshiped by humans) are so weak that they indirectly serve as evidence that there is in fact no god (otherwise there would actually be credible evidence for his existence).
7. While no argument can be conclusively prove that a god does not exist (or magical teapot or invisible unicorns) they none-the-less prove conclusively that the god’s currently worshiped now are in fact all non-existent.
8. The historical evidence for the divinity of Christ are so weak that a historian can credibly argue that Jesus may not have ever even existed (let alone die on a cross and ascend into heaven). Tacticus appears to be of the impression that Christians were named after a person named Chrestus and Josephus’ only reference to Jesus was that he was the brother of James. In fact, the only evidence that he rose from the dead are the claims made by a handful of individuals within the bible (many if not most of which were second and third hand reports).
In my time as a theist and during my many conversations with them, I have been able to determine that their beliefs (once mine) stem not from the truth but rather from a fear of the truth and a desire to believe that their existence has some pre-defined intrinsic purpose and value. Please let me know if your reasons for disbelief in god are not present (I'd like to know them).