Well, I’ll do my best. Forgive me for errors, I’m trying to type quick. This is partly from what I’ve garnered from the synopsis also.

“There are two way through life: the way of nature and the way of grace”

The mother figure represents grace, and everything that represents unselfish love, while the father figure (Brad Pitt) represents nature, which is cruel, competitive, selfish etc. The three boys (especially Sean Penn) are “wrestling” with the legacy of their parents. The Penn character as an adult is trying to figure out the meaning in his life and life in general as he is going through what I’m guessing is a crisis in faith and life. So where does he look for answers? His childhood, his family home–”our first schooling”, which can reveal a lot about who we are and where we come from, and even reaches the issue on a universal level (grace vs. nature–mother vs. father).

The cosmic sequences are to show that nature itself (not of just this world but the universe) mirrors even the smallest of all things–the family. We often think of the universe as a chaotic place (like a popular perception of the world), but in it lies the entity of unselfish love–the purity of what is human.