The instrumental part in the beginning and middle of the song closely resembles the melody in the theme from Chaplin's Limelight! I was sure I knew that melody from somewhere!
Anyway this makes perfect sense with the last part of the song:
To really feel the joy in life
You must suffer through the pain
When you surrender to the light
You can face the darkest days
Which is exactly what Chaplin tries to tell us in his movie Limelight.
I'm also quite sure part of the melody also resembles Cinema Paradiso's theme which wouldn't be the first time Dream Theater has referenced that movie
("ora che ho perso la vista chi vedo di piu"
- quote in Take the Time which is the old man in Cinema Paradiso saying:
Now that I've lost my sight, I can truly see
echoing int he song: I can see much clearer now I'm blind)
Please tell me I'm not crazy noticing these references? xD