Welcome to Dhamma Wheel.
Kenshou wrote:Buddhism is in general more concerned with how we experience things than their objective reality. Trying to fit all Buddhist concepts into an ontology produces awkward results.
This is a very good point and cannot be over-emphasised. So, what is the 'experience' of a shadow?
The variations in light can be observed, but it must first be determined (sankhata) as a shadow before it can be known as "a shadow". (This may or may not be what Goofaholix was getting at with his Zen-like koan).
The variations in heat can be felt. If it's a sunny day and you step under a tree, the diminishing of the fire element can be observed.
Remember that the Dhamma is about suffering and its cessation - it's not about chin-scratching and pontification. If what you're thinking about has no connection to suffering and its cessation, chances are you're not thinking in line with the Dhamma.