Overviews are provided for traditional and phylogenetic nomenclature. In traditional nomenclature, a name is provided with a type and a rank. In the rankless phylogenetic nomenclature, a taxon name is provided with an explicit phylogenetic definition, which attaches the name to a clade. Linnaeus's approach to nomenclature is also reviewed, and it is shown that, although the current system of nomenclature does use some Linnaean conventions (e.g., certain rank-denoting terms, binary nomenclature), it is actually quite different from Linnaean nomenclature.
The primary differences between traditional and phylogenetic nomenclature are reviewed. In phylogenetic nomenclature, names are provided with explicit phylogenetic definitions, whereas in traditional nomenclature names are not explicitly defined. In phylogenetic nomenclature, a name remains attached to a clade regardless of how future changes in phylogeny alter the clade's content; in traditional nomenclature a name is not “married” to any particular clade. In traditional nomenclature, names must be assigned ranks (an admittedly arbitrary process), whereas in phylogenetic nomenclature there are no formal ranks. Therefore, in phylogenetic nomenclature, the name itself conveys no hierarchical information, and the name conveys nothing regarding set exclusivity.
It is concluded that the current system is better able to handle new and unexpected changes in ideas about taxonomic relationships. This greater flexibility, coupled with the greater information content that the names themselves (i.e., when used outside the context of a given taxonomy or phylogeny) provide, makes the current system better designed for use by all users of taxon names.