The first answer that comes to mind is that shadows and lights are the engine behind human evolution.
It means that it is because of this polarization that we evolve as a human race.
We keep trying to improve and the idea of being better is what drives us forward.
If there was no shadow, there would be no motivation and just stillness.
So imagine that you are being guided on planet and that the totality of your existence happens within a playground with very specific manifestation laws.
Imagine that you are being guided by angelic forces in your evolution.
You have forces that stand in front of you and guide you forward.
And then there are forces behind you that push you forward, punish you, burn you when you fail the human tests.
The shadows is what you try to avoid because shadows can create pain either for you or others.
So, what comes to mind is that life happen within this vast evolutionary engine and shadows are what’s in the process of being dissolved, like an old program.
It is these old files, outdated codes that no longer contain the juice that the new life codes give you.
So, when you go back to these old codes and shadows you go against progressive human evolution.
The conflicts, challenge and pain that you experience when you go in shadow tell you that you are on the wrong track.
To avoid pain, you will try to stick to the lights and cultivate what makes you feel good.
So, in shorts, lights and shadows are life’s polarization that drives human evolution forward.