Much of the last chapter was devoted to highlighting the problems facing the contemporary Linnaean system. Those problems fall into two camps: theoretical and pragmatic. On the theoretical side, the original assumptions underlying the Linnaean system – essentialism, creationism, and Linnaeus's sexual system – have been rejected. The Linnaean categories themselves correspond to little if anything in nature; and their number is insufficient for representing life's diversity. On the pragmatic side, the Linnaean rules of nomenclature are sources of instability and ambiguity. Furthermore, they saddle biologists with the task of assigning ontologically vacuous and misleading ranks to taxa.

Given the theoretical and pragmatic problems facing the Linnaean system, should biologists continue using that system? The problems outlined in the previous chapter are sufficiently pressing that we should at least study the feasibility of replacing the Linnaean system with an alternative. However, this is no small task, nor should it be done lightly. The Linnaean system is firmly entrenched in biology as well as popular culture. Critics of the Linnaean system must build a persuasive case for rejecting that system. They must develop viable alternatives and show that at least one of those alternatives faces fewer problems than the Linnaean system. But that is not enough. Given the pervasiveness of the Linnaean system, critics of that system need to provide more than theoretical reasons for adopting an alternative system. They need to show that switching to an alternative system is practically feasible.