I think the fundamental misconception starts when you think about two things colliding or pushing or touching. I think the difficulty people have separating the objects and the forces they have applying to them is because they see this zero distance touching thing and their mind goes blank.
But that's not the way nature is. Even when two objects appear to be pushing on each other, actually they are repelling each other a short distance away due to electromagnetic repulsion. And physics doesn't really have extended objects that react like macroscopics. The basic physical theories predict point like objects that never crash into each other. String and branal theories might complicate things, but when they "hit" they merge, so its nothing like what people try to conceptualize when they see two bodies hit (and they're so small anyways, they're almost pointlike).
So how about this. Think only about two separated points and a field between them (like gravity or electromagnetism or boogeyboo). Newton's law says that the force one point experiences will be exactly the same strength as the force the other point experiences, in opposite directions. The moon pulls on the earth with the same force as the earth pulls on the moon, in opposite directions. A magnet pulls or pushes on another magnet just as much as the latter magnet pullsor pushes on the former, just in the opposite direction.
I really think its the two things "touching" which causes Giordano Bruno to burned...
