This is the very thing which makes up the virtue of the happy person and a well-flowing life — when the affairs of life are in every way tuned to the harmony between the individual divine spirit and the will of the director of the universe.Chrysippus, Quoted in Diogenes Laertius, Lives of the Eminent Philosophers, 7.1.88
For this quote the book talks about addicts struggling in a 12 step program where step 2 is acknowledge a higher power. At first glance this feels like a religious platitude, and it is not necessarily helpful to the nonreligious. But the point really has nothing to do with religion at all. The fundamental idea is to accept that the world does not revolve around us. It is much too big for that. We are not at the center, and we are not in control. We are simply along for the ride of life. As the book says, “As soon as you can attune your spirit to that idea, the easier and happier your life will be, because you will have given up the most potent addiction of all: control.” What a great way to phrase it — “attune your spirit to that idea.” How you think about and understand the world and your relationship to it is entirely within your control, and yet this is something that most people spend very little time thinking about.
I am not a religious man, and I have not been for a very long time. But I also figured out long ago that not being religious does not mean you cannot be spiritual. In the Neil DeGrasse Tyson interview with TIME magazine he is asked about the The Most Astounding Fact, and this helped me more concretely frame and explain my spiritual views ever since. You do not need to believe in a god to see the beauty and feel kinship with the Universe at large. In so many ways we are just a brief jumble of particles that have coalesced in a way for the Universe to view and experience itself. Our atoms will return on their journey before too long, and we should treasure the time given to us to experience this cosmic adventure.
When considering the big picture, we are not in control. We are along for the ride.