Atheism and Agnosticism

I consider myself to be both an atheist and an agnostic. Most people would consider that to be a contradiction - that atheism and agnosticism are mutually exclusive. They're going by definitions that are something like "Atheism is being sure there is no god" and "Agnosticism is not knowing whether or not there is a god." I don't like those definitions. I don't think they're useful, for two main reasons.

1. From a practical standpoint, they're the same. Neither the atheist nor the agnostic pray or go to church, or do anything religious like that. In terms of how they live their lives, there's no significant difference between the two. But internal belief can be just as important as external behavior, which leads to point 2.
2. It excludes a middle ground. Under this scheme, it seems there are two options of non-belief. Atheists think there is absolutely no possibility that god exists, and agnostics think it's fifty-fifty between there being a god, and there not being a god. Some people are somewhat more inclusive and consider any uncertainty to be agnosticism, so if you think there's a 10% chance of god existing, or a 1% chance, or a 0.0000001% chance, you're an agnostic. But then, virtually no one is actually an atheist, and it's a pointless distinction.

So, here are the definitions I prefer. Atheism is not believing in god, not necessarily being sure he doesn't exist, just probably. Agnosticism is believing that it is not possible to know for sure either way. Atheism is about ontology - what exists. Agnosticism is about epistemology - what we can know.

My reason for being an atheist is simple: I don't see any evidence for god, and the logical default is to conclude non-existence, unless there's reason not to.

My reason for being an agnostic is somewhat more complicated. First off, I'm talking about gods that are supposed to be omnipotent. Most everyone will agree that an omnipotent god can't be disproven. It's possible that he could just be hiding. Using his unlimited power to evade any attempt at detection. I also contend that it is impossible to prove that god does exist. Suppose god did reveal himself, and to prove it, switched the positions of Earth and Jupiter, but preventing any adverse effects on the Earth. Astronomers could verify that in fact the Earth and Jupiter had been switched. But this could merely be the work of some super-powerful alien. Not enough to prove god's omnipotence. So, god moves the whole solar system to another place in the galaxy, an even more powerful feat. But that again doesn't prove that he's all-powerful. So, he moves the galaxy, or a hundred galaxies or a billion galaxies. No matter how powerful a miracle was performed, there is always another one just a little bit more so. Now, all this would of course prove that there is some super-powerful entity, who from our perspective, is effectively omnipotent, but there's no way to show actual omnipotence, and if it's not omnipotent, it's not god.