Well, I guess a better question is how could he ever sit as a spirit? So, you know, there's always a canonical interpretation to those things. Like, it's been an allegory to somehow understand things that are beyond our logical grasp blah-blah-blah. Other religions are no better in this respect. In Judaism, for example, you have a very nice little concept of Tzimtzum Tzimtzum - Wikipedia, the free encyclopedia which basically tries to reconcile a logical discrepancy between the monotheistic 'infinite' definition of God and the fact that the humble finite species could exist bearing their own personal responsibility (and thus a potential personal reward or punishment).