Principios de Taxonomia

Introductionj3
reproductive community. This concept is based on mutual lateral gene exchange by
sexual contact. Organism A belongs to the same species as organism B if any of its
offspring does receive genes from organism B.
The concept of the species as a gene-flow community is a species concept based on
mutual relational connections among the organisms and their offspring (Chapter 6).
It is not a typological species concept based on trait similarities. The concept of the
gene-flow community is not easy to understand. It contradicts a type of cognitive
presetting in the human mind (Chapter 2), and most importantly, it is very difficult to
use. Ultimately, it is inapplicable for use in an operational and pragmatic everyday
taxonomy. However, the concept of the gene-flow community appears to be the only
species concept that reflects an entity that exists as reality as a delimited group in
nature. According to this species concept, the borders between the species (although
penetrable) exist in nature; they do not result purely from human constructs used for
the purpose of grouping individuals.
The fundamental disagreement between a species concept that is logically consistent
and a species concept that is applicable in practice is the primary reason for the
existence of a species problem that could not previously be resolved. This deep
conflict has its roots in the incompatibility between the claim to classify biodiversity
according to taxa, in the sense of Linnaeus, and the scientific fact, introduced to the
world by Darwin, that the traits of organisms change over time (Chapter 2).
This book has a long history. The book s inception occurred almost twenty years
ago, when I became aware that the biological phenomenon of multiple allelic
polymorphism implies a serious problem for taxonomic classification. How can
organisms be classified into different species if single organisms already differ in
hundreds or even thousands of their traits? Doesn t this mean that there must exist
two different types of traits? One type of trait serves to discriminate among
individuals within the same species, whereas other types of traits must possess
certain unique qualities to be suited for species discrimination. However, two such
types of traits do not exist (Chapter 4). Accordingly, what difference separates
individual differences and species differences?
This book addresses biologists and philosophers, although it is much more a
biological than a philosophical book. During the long time of the progress of this
book, I benefited greatly from Markus Werning (now University of Bochum), who
taught me several basic elements of philosophy. I also thank Gerhard Schurz
(D€usseldorf), who opened the door for me to enter the philosophic scientific
community. A decisive role in the continuation of my efforts to bind taxonomy to
philosophy was played by Hartmut Greven (D€usseldorf), who encouraged me not to
give up. He eased the difficulty for me, as a geneticist and molecular biologist, to gain
entry into the taxonomic scientific community by inviting me to give lectures and to
publish preliminary papers on the species problem. I also thank Sebastian L€obner
(D€usseldorf), who is a linguist, not a biologist, but his invitation to be a member of his
research group on functional concepts had a great impact on the understanding of
taxonomic class formation presented in this book. Finally, I thank Gregor Cicchetti
and Andreas Sendtko for their decision to support the processing of this book by the
Wiley-Blackwell publishing company.