The short answer to the question posed by Ghiselin (1989) in his first paragraph is no. A fallacious argument is one whose premises fail to support its conclusion. One type of fallacious argument is argument by ad hominem attack, e.g., when one supports one's position by impugning the motives or character of one's opponents. For further details see any textbook in logic; for further examples see Ghiselin's reply to us.
Ghiselin implies intentional misrepresentation in our quote of his views on the applicability of the biological species definition to plants. However, our quote was from the draft of his paper we had to work with; the additional words were added in Ghiselin's final printed version, not seen by us. In any case, the added words do not make his position any more satisfactory -in fact they degenerate into question-begging. Ghiselin wishes to win the argument about species by definition, simply by calling the cases that don't fit his favored definition "non-species". We shouldn't accept such voodoo ontology.
Species formation (in the broad sense of genetically and morphologically defined lineages) is a matter of empirical observation. There are observable lineages out there in the natural world, although it is certainly likely that different processes are responsible for the origination and maintenance of lineages in different groups. The insistence of the biological species concept on the primacy of contemporaneous patterns of gene flow (interbreeding) as causal factors in the diversification of lineages has been a major factor in holding back progress in evolutionary biology. The phylogenetic species concept (PSC) as advocated in Mishler and Brandon (1987) is designed to reflect both what is general about species (i.e., that they are lineages) and what is special about species (i.e., that causal factors differ) in different groups of organisms.
Ghiselin states that we have come up with a reason (albeit a bad one, according to him) to place every organism in a species. What is the reason? Ghiselin does not make this clear, nor can we help since we do not believe that every organisms must be placed in some species or other. Indeed we explicitly stated (Mishler and Brandon 1987: 410) that "a corollary of the PSC is that not all organisms will belong to a formal