In the final analysis the hierarchic pattern is nothing like the straightforward witness for organic evolution that is commonly assumed. There are facets of the hierarchy which do not flow naturally from any sort of random undirected evolutionary process. If the hierarchy suggests any model of nature it is typology and not evolution. How much easier it would be to argue the case for evolution if all nature's divisions were blurred and indistinct, if the systema naturalae was largely made up of overlapping classes indicative of sequence and continuity.