Natural selection awards no prize for second place. - Thomas Lewis

Like any other momentous shift in emotion, depression is not an occupation by a foreign army; it is civil insurrection, the subversion of identity's republic from within. A depressed person loses more than energy and appetite — he loses himself and the capacity to make the decisions his former, pre-coup self would have made.

Proof that expressions are intrinsic is closer at hand than the South Pacific. As Darwin knew, a congenitally blind baby will smile while interacting pleasurably with his mother. Such a smile comes from a developing creature unable to speak, walk, or even sit up, but he already knows how to express happiness through a configuration of muscular contractions he has never seen on anyone’s face.

The purpose behind discerning the nature of love is not to satisfy ivory tower discussions or to produce fodder for academic delectation. Instead, as our work makes all too clear, the world is full of live men and women who encounter difficulty in loving or being loved, and whose happiness depends critically upon resolving that situation with the utmost expediency.