Upload & Sell: On
Thanks ... my analogies usually "bomb" around here, so it's always nice to know that one connected along the way.
At the risk of inserting another one that doesn't fare as well ... think about what happens to the billiard balls following a break. The applied energy disperses in a radial direction ... yet each ball continues to follow along its individual path, reflecting off the rails iaw with AI=AR. If it weren't for the force of gravity and the friction of the felt, as well as the energy absorbed by the rails they are reflecting off, they would continue indefinitely along the straight line path from which they originated and subsequently acted upon by the rails iaw AI=AR.
The ricochet from a shotgun blast also might aid in the concept. The initial dispersion of the shot from the barrel will radiate (in concert with the choke), but the path of each of the pellets will continue on a straight path, each one at a different angle from the others. Should one of those pellets strike an object and ricochet (i.e. reflect), it will continue to follow a straight line path iaw. AI=AR. It too would continue indefinitely, if it were not for the force of gravity to pull its vertical axis down to the ground. Light, however requires much more than the earth's gravitational pull to alter its straight line path, and as such continues along its straight line path, except as acted upon by other objects, where AI=AR continues to apply (index of refraction, also).
Point being ... ISL pertains to point source dispersion, not reflection (as Guari and others have duly noted) ... and camera to subject distance is NOT responsible for exposure due to ISL theory being applied to reflected light.