Ed: Thanks for your creative remarks. They are the kind of specutation that I love but, as I'm personally discovering, many miles and much work remain to show post-CVA depression as a complex adapted system. You might check out George Williams, "Adaptation and Natural Selection" for guidelines to showing a set of behavioral routines as an "adaptation." Generally, a CAS (1) solves a problem tied to reproduction, (2) has some physiological subcomponents, (3) works efficiently to process complex information and stage response sequences, (4) cannot be parsimoniously described by concepts from physics, chemistry, etc. (e.g., a flying fish lands in the water, is this due to an adaptation or to gravity?) Williams tries to keep all of us respectable by urging that "... adaptation is a special and onerous concept that should be used only when it is really necessary." Nonetheless, guys like you and me can have some fun so long as we know and appreciate the massive work that is involved to make the point (kind of like sponsoring an idea for Pope).