As our eyes, minds, and hearts/emotions/spirits travel over what is in the picture and work to make sense of it all, they privilege certain elements of the composition, foregrounding some, which has the relativistic effect of causing others to recede (regardless of their "true" position in the picture).
The way each picture is "framed" (think perspectives here) also makes a huge difference as to what appears to be foregrounded, etc.
So the resulting composition is as much a product of the position of the viewer and of the forces the different "pieces of the view" exert on it as it is of what is actually on the canvas. The interaction of the various elements is dynamic, not static, and may vary depending on the nature, intensity, and angle of the light hitting it at any given moment.
1) The physical senses, the mind, and the emotions each exert a force on our physical reality.
2) Because the mind, the heart, and the senses are connected—when one exerts a force, it affects the others—and because the elements of our physical reality are connected, when a force is exerted on one element of the reality, it affects other facets as well. If forces are exerted in disproportionate ways, they have the potential to distort the resulting picture.
3) Our thoughts and our choices control, to a great extent, the type, amount, and recipient of the forces.
MY AHA :
Perhaps balance (in art, in life, in relationships) isn't so much about the quantity of A vs. B vs. C as it is about composition, position, and perspective!