Do you own the shadow cast by trees on a bench if you come to the park every day?  The paradox lies in that it seems your own; you got accustomed to it, became intimate with it and came to love it.  You involuntarily became the source that throws light.  Unlike the unemotional "cold" sun, a person that came to love the shadow radiates warmth - the warmth that is neither rational, nor practical, and it eludes accurate analyzing or computation.

In Speak, Memory, Nabokov called it an "individual mystery":
"[Through the train window,] I saw with inexplicable pang, a handful of fabulous lights that beckoned to me from a distant hillside, and then slipped into a pocket of black velvet:  diamonds that I later gave away to my characters to alleviate the burden of my wealth".

По-русски