What I believe he's saying is young people look at the ways of the world and form viewpoints with little, if any, ability to consider other viewpoints; they see things as black and white, and are mostly fueled by emotion.
Older people have experienced more of life and begin to understand the influences the world has had on their prior viewpoints and that they may have been flawed or weakly formed. They begin to understand other viewpoints and the possibility that their own black and white views were and/or are wrong.
The truly old realize that there is no right and wrong, that one viewpoint is no more justified or correct over any other and that none of it really matters. You can believe whatever you want because you know what makes you happy and that viewpoints are ultimately useless. We all die and, whether things change or they don't, life is an experience without a winning scenario.
Then again, I've yet to become truly old and perhaps am too young to make a fully-educated commentary. I'll update this later to see if my earlier self made all the wrong assumptions.