While love is common, true love is rare, and I believe that few people are fortunate enough to experience it. The roads of regular love are well-traveled and their markers are well understood by many- the mesmerizing attraction, the ideational obsession, the sexual afterglow, the profound self-sacrifice, and the desire to combine DNA. But true love takes its own course through unchartered territory. It knows no fences, eludes modern measurement, and seems scientifically woolly. But I know true love exists. I just can't prove it.
from The Evolution of Desire