His response on Reddit when asked "What can you tell a young man looking for motivation in life itself?" 

“The problem, often not discovered until late in life, is that when you look for things in life like love, meaning, motivation,

it implies they are sitting behind a tree or under a rock.

The most successful people in life recognize, that in life they create their own love, they manufacture their own meaning,

they generate their own motivation.

For me, I am driven by two main philosophies, know more today about the world than I knew yesterday. 

And lessen the suffering of others. You'd be surprised how far that gets you."

--Neil deGrasse