We seek the Light because we are that Light. Be good to yourself. Flee from darkness, keeping it behind you at all times. Be hopeful, and when hope seems far away, pray for it to return to fill you back up. Faith and Hope are the seeds of happiness and freedom from the things that tend to haunt us and temp us towards the darkness.
A more pure physical condition is the foundation of a good or better life experience. Clean air, lungs, psyche are married for life.
One who doubts the existence of Light and darkness is destined for foolishness.