Defining viral species: making taxonomy useful

Virus taxonomy at present is best characterized as a categorization of convenience, without a firm basis in the principles of evolutionary biology. Specifically, virus species definitions appear to depend more on tradition and popular opinion among virologists than on firm, quantitative biological evidence. I suggest a series of changes to underlying species concepts that would shift the field from one that simply files viruses away in taxonomic boxes to one that can learn important biological lessons from its taxonomy.