Love is the engine, but love is not remembered

So writes Charles Bowden, in the award-winning Some of the Dead Are Still Breathing. 

This is an "environmental" book, but I don't believe Bowden ever mentions that word. Yet unlike nearly every other book about nature I can think save a couple written by John Muir or Edward Abbey, this "environmental" book does bring up "love" and/or "sex" quite frequently…and even bawdily. 

Bowden writes:

Love is the engine, the only thing that matters, the sensation that moves the planet down some path that makes today look less than tomorrow. And love is not remembered. The wars, the rich, the blues men beating their women, the long drag off that joint, the killing ground, these get remembered. Along with famines, plague, and those other two horsemen riding death through the duly recorded pages. But not love. It simply moves things. All the forgotten mothers. And lovers. And eager lips facing down history and reaching for warmth amid the cold stars of midnight. 

I believe this. But I cannot clearly tell you what love is. 

Bowden is not being sentimental here; in another passage, he mocks those scientists who would attempt to chalk up every quirk of every creature's behavior by "evolution" or "instinct." He's simply puzzled — and fascinated by love. Reading this book about the natural world, one wonders: why is this so rare?