1. It is possible that a maximally great being exists.I pointed out that this was a bare assertion before ... but let's examine this more closely.
The fact that we can imagine something - a maximally great being, for example - is no reason to presume that such a thing exists. We can imagine giants, but they don't exist. We can imagine unicorns, but they don't exist, we can imagine that your neighbor has an invisible fire breathing dragon in his garage, but it doesn't exist.
If we take the construction of a maximally great being, and replace it with any of the lesser, but similarly ludicrous claims above, we can assert an argument that says that anything we can imagine exists, and thus exists "in all possible worlds".
That. Is. Simply. Stupid.