What is the theme in Einstein's Dreams by Alan Lightman?

Being stuck in time is the main theme of the book. Throughout the novel, many of the characters become stuck in time. Some of the characters become stuck psychologically, like the man who is obsessed with his achievements in high school. Other characters become stuck physically in time, like the doctoral student who decides not to face his fears and move forward in time. He remains in the comfortable study of his mentor, never finishing his doctorate or moving on to his future. In all of these instances, being stuck in time is isolating. Other people move on with their lives or become stuck in different moments, and each person who is stuck in time is isolated.