I didn’t understand this quote out of context so I followed one of the links and he explains it in this comment:
It’s something I learned from animal ethology. An “overdetermined” behavior is one for which there are multiple sufficient explanations. To unpack: “For every interesting behavior of animals and humans there is more than one valid and sufficient causal theory.” Evolution likes overdetermined behaviors; they serve multiple functions at once.
Eric S. Raymond: “Interesting human behavior tends to be overdetermined.”
Example sources:
http://esr.ibiblio.org/?p=4213
http://esr.ibiblio.org/?m=20020525
http://esr.ibiblio.org/?p=6599
I didn’t understand this quote out of context so I followed one of the links and he explains it in this comment: