[Catwoman]

You agree then, that 'we may acquire concepts by our perceptual experience of physical objects. But we would be mistaken if we thought that the concepts that we grasp were on the same level as the things we perceive'.

Plato's cave suggests we see but a shadow of what actually exists. But is a physical entity (so-called 'reality') creating the shadow - or is the shadow just as tangible? Is the cause of the shadow any more 'real' than the shadow itself. Maybe perception is reality and substance has nothing to do with it.