There are many practical problems with the proposal to adopt PC, for example:
- Adoption would cause major instability both in the change over period which would require two codes working in parallel and according to some it would also be more unstable when adopted. The ICZN has worked very hard for the existing state of stability, and this would be a significant step backwards.
- PC does not cover species names, so the Code will still be needed for these, there is no philosophical reason for this inconsistency, merely the PC cannot practically “convert” the existing animal species names to phylogenetic definitions in the foreseeable future with the resources they have.
- Even if PC is adopted for names above the species group, not everyone will adopt PC, so there would be the problem of coexistence with names diverging in meaning, undergoing different nomenclatural treatment by each code, and the resulting confusion.
- PC is only a draft at present, so it is not in force, currently there is no clear indication when or if it will become active; it may turn out to be a “castle in the air”.
- • PC is in effect untested in the real world, whereas the Code has 100+ years of development and combined experience of what works and what doesn’t (see the extensive ICZN publications of Cases official Opinions etc.). This is not to say that the Code is perfect, it is currently evolving to be fit for the 21st century. For example there are initiatives to implement centralised registration of names and develop an authoritative list of available names in an electronic tool called “Zoobank”; to change the rules on what constitutes valid publication to accommodate electronic publication modes; and to restructure the Code in its next (5th) edition. These are challenging topics, however the ICZN is likely to carry these forward with more success than PC because ICZN is already well advanced in these topics and has a more universal mandate.