What it means to put it mathematically is that, if you're concerned about a society today, you should be looking not at the value of the mathematical function -- the wealth itself -- but you should be looking at the first derivative and the second derivatives of the function. That's one general theme. A second general theme is that there are many, often subtle environmental factors that make some societies more fragile than others. Many of those factors are not well understood. For example, why is it that in the Pacific, of those hundreds of Pacific islands, why did Easter Island end up as the most devastating case of complete deforestation?
Ako to postavimo matematički, proizlazi da, ako ste zabrinuti za društvo danas, ne biste trebali gledati vrijednost matematičke funkcije, odnosno samo bogatstvo, već biste trebali gledati prve i druge derivacije te funkcije. To je opće pravilo. Drugo opće pravilo jest da postoji mnogo suptilnih faktora u okolišu koji neka društva čine osjetljivijima od drugih, a mnoge od tih faktora ne razumijemo u potpunosti. Na primjer, zašto su na Pacifiku, od stotina otoka, baš Uskršnji otoci postali slučajem najgoreg i potpunog raskrčenja šume?