The Theoretical Costs of DNA Barcoding

I begin with a description of the benefits and limits of DNA barcoding as presented by its advocates not its critics. Next, I argue that due to the mutually dependent relationship between defining and delimiting species, all systems of classification are grounded in theory, even if only implicitly. I then proceed to evaluate DNA barcoding in that context. In particular, I focus on the barcoders’ use of a sharp boundary by which to delimit species, arguing that this boundary brings along additional theoretical commitments inconsistent with the way taxonomists conceive of species, viz., as entities that have vague boundaries and that cannot be defined by any single attribute other than ancestry. Given these inconsistencies, I conclude that even if groupings based on DNA barcodes match those of an existing taxonomy, the two systems of classification are not necessarily tracking the same entities, i.e., species.