Abstract—The parsimony criterion both measures the ability of genealogical hypotheses to explain observed similarities and corresponds to Hennig's principle of grouping by synapomorphy. Sæther's proposal of grouping according to homoiology is neither Hennigian nor justified on any other grounds. Criticisms by Felsenstein that parsimony analysis may be statistically inconsistent lead to an equivalent criticism of all statistical methods, and so are of no value for evaluating phylogenetic metho