What notions of good and evil are in the novel 'The Road'?

One of the motifs of the story is the father and son remembering that they are "the good guys". They are perhaps, the last remnants of good left in a world that is rotting before their eyes. The boy, in particular, is a Christ-figure, a symbol of goodness in a world that has lost its soul. The boy is perhaps the only light left in the darkness. He represents all that was good in humanity after humanity destroyed itself.