In the way that it can be removed, imaginatively, from the picture and we can still have "a picture," it is not integral to the picture. With or without gravity, or any individual bit, the picture of "what is" would still be a picture of "what is" (however different a picture that might seem).
An analogy for the fundament in the "picture" would be the canvas contrasted to things that are painted, in live-motion, on the canvas. We can paint gravity here, in the interactions between illuminated objects, but if we didn't paint "gravity" we could still have a picture.
Very well said.
Beaudreaux, when people say they can't imagine existence actually existing without God they aren't saying that they can't imagine being wrong. Take pantheism for example (a viewpoint that most of the posters have at least roughly presented) this is, simply put, the belief that God literally is everything. Therefore it follows that without God nothing exists. You may aswell ask "what would cake be like if cake didn't exist?".
Now just for a moment I'll answer your question in accordance with MY views on deities. First off there is God (capital G) who literally is reality. Obviously then, without reality, reality doesn't exist.
Other deities, angels, demons and various other "spiritual" entities do not have to exist for reality to exist and the vast majority of humans would be completely unaware of their absence. For those who are aware of these entities however, the sudden loss of these beings would probably be too much to take and would most likely drive them mad.
Assuming these entities NEVER existed, then I would imagine the only difference humanity would face is a reliance on their own abilities for magical purposes. Again, this is something that doesn't affect the vast majority of people.
Simply put, without some of these entities, life would be just that little bit more bland.