Piet Hein

Poul Anderson, Genesis (New York, 2001) is divided into Parts One and Two, each with an internal title page.

Part One, p. 1, has this appropriate quotation:

"To follow knowledge like a sinking star,
"Beyond the utmost bound of human thought."
-Alfred, Lord Tennyson.

No surprises there. We recognize both the name Tennyson and the relevance of the verse.

Part Two, p. 99, has:

"Was it her I ought to have loved...?"
-Piet Hein.

Observations
I googled Piet Hein. See here.
When I googled the quotation, I found only copies of Anderson's text.
Hein refers to Niel Bohr who is also referenced in Anderson's Three Hearts And Three Lions. See here.
In Anderson's use of the quotation, does "her" refer to Earth?