There are shadows for the shadows of things, as a reflection seen in a mirror of a mirror. We know there are circles within circles and dimensions beyond dimension. Reality is itself a shadow, only an appearance accepted by those whose eyes shun what might lie beyond.

Shadow is an amazing subject. Shadow is an absence. As an absence of energy you can compare it to silence or maybe cold air....We talk about photography being simple and architecture being complex and how do you convey something that is more deep, that allows you to dream or think This is weird so you start to dream and think and you maybe go out purely from the picture but into yourself. The light and the shadow are tools to allow you to do that.

Most people think that shadows follow, precede or surround beings or objects. The truth is that they also surround words, ideas, desires, deeds, impulses and memories.

Shadow is the diminution alike of light and of darkness, and stands between darkness and light.

Shadow is not the absence of light, merely the obstruction of the luminous rays by an opaque body. Shadow is of the nature of darkness. Light is of the nature of a luminous body; one conceals and the other reveals. They are always associated and inseparable from all objects. But shadow is a more powerful agent than light, for it can impede and entirely deprive bodies of their light, while light can never entirely expel shadow from a body, that is from an opaque body.

All shadows have their light, each shadow being an autonomous unit forming a new individuality with its own chiaroscuro: it is no longer a form that is half-shadow, half-light, as hat hitherto been the case.

This is good, and all good things cast shadows.

A shadow may be infinitely dark, and also of infinite degrees of absence of darkness. The beginnings and ends of shadow lie between the light and darkness and may be infinitely diminished and infinitely increased. Shadow is the means by which bodies display their form. The forms of bodies could not be understood in detail but for shadow.

Everything that we see is a shadow cast by that which we do not see.

The Shadow. It cannot be grasped. Chase your shadow and it will, flee; turn your back on it and it will follow you. It is also a person’s dark side, the thing that makes them mysterious. After they have given us pleasure, the shadow of their withdrawal makes us yearn for their return, much as clouds make us yearn for the sun.

We and the flowers throw shadows on the earth.
What has no shadow has no strength to live

Even in art, there is no light without shadows, and no shadows are cast without some light. Even the shadow of Adolf Hitler is accompanied by some light.

...shading is of great importance, and good shadows can best be secured when the sun is low, and when one side of all objects is more strongly lighted than the other.

Do shadows cast shadows of their own?