Lyric discussion by maclmart 

Cover art for Timshel lyrics by Mumford & Sons

Here is an except from Steinbeck's East of Eden that correlates directly wit the lines "And you have your choices And these are what make man great His ladder to the stars"

"But 'Thou mayest'! Why, that makes a man great, that gives him stature with the gods, for in his weakness and his filth and his murder of his brother he has still the great choice. He can choose his course and fight it through and win"

I believe the song is all simply about this great choice, not anything terribly specific such as the choice of abortion.