There are two fire symbols in the book. The fire of destruction or purification that cauterized the world and the fire the man and boy carry. That is the fire to live and the fire of hope and the fire of determination. The ash from both fires is everywhere.
At this site she talks about her ideas of the symbolism. http://74.125.95.132/search?q=cache:Gy4tFZ4YS9gJ:www.ninetyandnine.com /word/2007/07/review-of-road-by-cormac-mccarthy.html+the+road+cormac+m ccarthy+symbolism&cd=3&hl=en&ct=clnk&gl=us

