Principios de Taxonomia

2.7 Can a Scientist Work with a Species Without Knowing what a Species is?j23
revolution has markedly revolutionized taxonomy (Dupre, 1999), this discipline still
seems to cling to the traditional Linnaean concept of an essentialist philosophy.
Darwin himself noted this and ultimately denied the existence of species: Since
species continue to evolve, they cannot be defined, they are purely arbitrary designations.
The taxonomist no longer will have to worry what a species is. ...This, I feel
sure, and I speak after experience, will be of no slight relief. (cited in Mayr, 1982).
Darwin thus realized that he had entered into a contradiction between the purpose of
classification and the theory of evolution he had founded.
Mayr criticizes this attitude of Darwin s by making the important point that
Darwin s perspective only refers to the typological species concept. It is just the
perception of a species as a class that has been turned into a human-constructed
artificial product by the theory of evolution, not the perception of a species as a group
of organisms held together by cohesive relationships. If a species is considered as a
group with a common genealogical descent, that means in which there is coherence
between parents and their children or if a species is considered as a community
where there is gene flow via sexual partners, the species does not conflict with the
theory of evolution. Such cohesive groups unequivocally prove themselves to be
natural and not human constructs. Descent coherence and sexual coherence
unquestionably specify real groups. However, if you do not view the species as a
class that is sorted on the basis of trait resemblance, it must be admitted that trait
resemblances, although they might play an important diagnostic role, are never the
ontological criterion for the status of a species (Sterelny and Griffiths, 1999) (see the
Section below It is one thing to identify a species, but another to define what a
species is ).
2.7
Can a Scientist Work with a Species Without Knowing what a Species is?
Can a scientist work with species without knowing what species are? This question is
not easily answered. Initially, everyone would say Of course not. However, it may be
possible for a taxonomist to sort and group species. This would then be a purely
pragmatic approach, just as a doctor can cure a disease without being able to define
what a disease really is. Thus, it is apparently possible to use things successfully
without knowing what these things are. It is indeed difficult to say what a disease is.
What trait distinguishes disease from health? Try to define both what disease is and
what health is. Is a pain in the calf a disease? Is age a disease?
Francis Crick, codiscoverer of the molecular structure of DNA, once said something
to the effect that you do not win battles by discussing what a battle is. In other
words, you can win a battle without knowing what a battle is. In contrast, the
biophilosopher David Hull said that We must resist at all costs the tendency to
superimpose a false simplicity on the exterior of science to hide incompletely
formulated theoretical foundations (Hull, 1970). Many philosophers of science
warn against a scientific mode of reasoning that is defined completely operationally
without being founded on a theoretical basis (Hull, 1968).