There's a misunderstanding. I agree that there is no good definition of species. However, there is a good definition of clade, taxon, or monophyletic group. The

There's a misunderstanding. I agree that there is no good definition of species. However, there is a good definition of clade, taxon, or monophyletic group. The author is suggesting that paraphyletic and polyphyletic taxonomical groups that are based on biases, intuition, or morphological similarities. We should distinguish between groups based on traits and groups based evolutionary history, and not conflate the two.