How does the author show us that Ralph is finally beginning to face the realities of their existence?

In chapter five Ralph has realized that getting through to these boys is tricky. He knows that he always has to be on his feet. He understands the weariness of life, where everything requires improvisation. In chapter 6 Ralph again gets frustrated and then asserts that it would be better to climb the mountain and rekindle the fire. He accuses the boys of losing sight of their original goal, finding and killing the beast. Contradicting Ralph, Jack states that he wishes to stay where they are because they can build a fort.