Cole realizes that he is small and insignificant in nature, and all alone. 

Cole is a very angry young man.  He blames everyone else for his shortcomings and his mistakes.  When he agrees to Circle Justice, he does not really plan to change.  He thinks the whole thing is a joke.  

The experience of being alone on the island is a wake-up call for Cole.  He is left there to fend for himself, and he is expected to reflect.  He acts out at first.  He tries to swim away.  He burns down his cabin.  Worst of all, he attacks the Spirit Bear. 

Trying to swim away is an awakening for Cole.  He is unsuccessful, and ends up in pain on the shore.  He has failed, and he is trapped. 

Then he became aware of another feeling. Stronger than any burning in his arms and belly, more haunting than the darkness that surrounded him, was the realization that he was alone, totally alone with himself.

And it scared him. (Ch. 5)

When Cole attacks the spirit bear, he is acting out of his usual anger.  Cole thinks that the bear should be afraid of him.  He is angry that it isn’t.  When the bear casually mauls him, it is a shock to Cole.  He realizes that the universe does not answer to him.  He is actually very small and insignificant in the grand scheme of things.

Badly injured, Cole assumes he will just have to stay there until he dies.  During the storm, he ponders the meaning of his existence.  He watches some baby birds die.  The world continues, and nature rages on, and Cole is unimportant. 

Eventually, Cole is rescued.  He becomes a different person after he recovers.  It is still a long road to recovery, because Cole has far to go, but he becomes less angry and more reflective.  He really does change because of the Circle Justice lessons.