How, for instance, does general voyeurism relate to the myriad foot fetishes people can have -- of which the gas pedal foot fetish you mentioned is not the weirdest. Does the specific imagery involved with a fetish matter? Or are all fetishes basically the same with the only significant characteristic of a fetish being the intensity of a person's desire to indulge it? For instance, is it meaningful to distinguish between someone who has a leather getish and someone who prefers latex, or even someone whose sexual experience is enhanced by certain kinds of music? Or is it more meaningful to relate the strength of people's desires for their fetishes?
If the particular interest of a fetish is not important, then a simple "hyper-sexual/hypo-sexual" dimension might suffice.
Holy shit...this is why dialogue is so great!
Chris
A rough 2D representation of sexuality
But it could be related more accurately to a 2-dimensional representation of a 3-dimensional color spectrum, relating colors to luminance and chromaticity:
The 1976 CIE Chromaticity Diagram
If you imagine that your "phylogenetic tree of sex" replaces the divisions with the color names shown on the field, then you can see what I'm talking about. The discrete parts of the phyla can be related in a generalizing way to the spectrum.
