Now that's an argument built on a shaky foundation, Celsius.
It is philosophically impossible to be an atheist...
Well, we know that's not true because philosophically I AM an atheist. There is also empirical evidence on this board that there are others here that are also atheists philosophically. And all philosophy really boils down to is a point of view.
... since to be an atheist you must have infinite knowledge in order to know absolutely that there is no God.
Well, that is interesting premise, but in actuality all I have to do is believe.
Atheist: Has faith that there is no god.
Theist: Has faith that there is a god.
Since all that is necessary for you is to have faith that something invisible exists, then, all that is necessary for me as an atheist is to have faith that something invisible does not exist.
But to have infinite knowledge, you would have to be God yourself.
Well, I suppose if that is your definition of god, you might go down this path. But since I don't believe in one, the definition of one is immaterial.
It's hard to be God yourself and an atheist at the same time!
I would think that could be the source of some significant cognitive dissonance there, but somehow I don't seem to be worried!