The South African scientists studying the bodies and bones of living and extinct people in the first half of the twentieth century were working with a scientific philosophy firmly rooted in the work of Carl Linnaeus done two centuries earlier. Linnaeus, the father of systematic biology, spent his entire scientific career attempting to name and describe all of God's creation. He felt that his labours would reveal the Creator's plan in the Great Chain of Being. Each link of the chain was represented by a separate species, and the arrangement of the species on the chain, from simple to complex, represented God's plan as revealed by anatomy (Lindroth 1983, 24).

Linnaean classification required a precise and fixed definition of each species so that this order could be uncovered. Each species had to be invariable and unchanging for Linnaeus's system to make sense (Lindroth 1983, 24). Linnaeus began in his later years to accept that new varieties could and did appear, but he downplayed their importance. Linnaeus felt these deviations were at odds with nature, and in particular with the nature of the species (Eriksson 1983).

The Linnaean vision of fixed species was an outgrowth of the philosophy of Plato. The Platonic view considered that each species had an eternal ideal or essence. This was the archetype, or original form of the species. Linnaeus adapted this to his concept of a species in which he ‘considered that the archetype was the most important measure of a species’ (Magner 1979, 353). To describe a species was to describe its archetype and variations were only shadows that departed from the original pure ideal.

In his first edition of Systema Naturae, Linnaeus catalogued human races as full species in their own right, but by the tenth edition he had transformed the races of humanity into varieties. But these races did not fit his standard approach to varieties. Each was provided with a brief description of its essence and its own name in Latin as if it were still regarded as a separate species. Linnaeus clearly intended these human variants to be considered fundamental units in the order of nature.

The Linnaean concepts of classification and archetype found fertile ground in the natural sciences and, particularly, they became firmly rooted in the young field of anthropology.