Sacrificing the world

I am currently reading The History of Love, by Nicole Krauss, for a bookclub I am in. So far I like it. One of the plot lines is written by a teenage girl from a family in which the father dies. Here is an observation she makes of her mother.

18. MY MOTHER NEVER FELL OUT OF LOVE WITH MY FATHER

She's kept her love for him as alive as the summer they first met. In order to do this, she's turned life away. Sometimes she subsists for days on water and air. Being the only known complex life-form to do this, she should have a species named after her. Once Uncle Julian told me how the sculptor and painter Alberto Giacometti said that sometimes just to paint a head you have to give up the whole figure. To paint a leaf, you have to sacrifice the whole landscape. It might seem like you're limiting yourself at first, but after a while you realize that having a quarter-of-an-inch of something you have a better chance of holding on to a certain feeling of the universe than if you pretended to be doing the whole sky.

My mother did not choose a leaf or a head. She chose my father, and to hold on to certain feeling, she sacrificed the world.