Just a thought on the ontological argument...
Perhaps it relies on the already existent belief.
For a theist, God exists. Since they can conceive that it is better for the most perfect being to exist in reality, the argument works.
However, for an atheist, the most perfect (none greater can be conceived) being existing in reality would be no greater than not existing. In fact, this must be a terrible fact that spites their worldview. In this case, the argument breaks down.
As such, we see that faith precedes reason (just as Anselm claimed). Our reason is always an extension of what we believe. Though we can drive this in reverse, the initial (and most natural) step is from faith to reason. Whether an atheist or a theist, this fact holds.