  Carlo Cipolla's stupidity quadrant and his five laws of stupidity were
proposed for the first time in 1976. Exposed in a humorous mood by the author,
these concepts nevertheless describe very serious features of the interactions
among human beings. Here, we propose a new interpretation of Cipolla's ideas in
a biophysical framework, using the well-known predator-prey or "Lotka-Volterra"
model. We find that there is indeed a correspondence between Cipolla's
approach, based on economics, and biophysical economics. On the basis of this
examination, we propose a sixth law of stupidity, additional to the five
proposed by Cipolla. The law states that humans are the stupidest species in
the ecosystem.
