Frozen Evolution. Or, that’s not the way it is, Mr. Darwin. A Farewell to Selfish Gene.

In contrast to the more or less single nominalist concept, there are a number of realistic concepts of species (e.g. historical concept of species, essentialist concept of species, structuralist concept of species). They are all based on the concept that species and the boundaries between them are objectively present in nature, independently of man’s will. The individual realistic concepts differ primarily in what they consider to be the cause of the distinctness of the individual species.