The question of origins has always fascinated the human mind. From the earliest times, the existence of life has mostly been attributed to supernatural intervention. However, naturalistic models of origins based on logic and philosophy can be traced to about the fifth century BC in Greece. Plato (428-348 BC) and Aristotle (384-322 BC) were the philosophers that probably had the greatest impact on western thought. Their idealistic view of striving for perfection laid the foundations for a naturalistic view of origins.
Plato's idealistic views had a profound effect on biology. To him, the structure and form of organisms could be understood from their function which in turn was designed to achieve ultimate goodness and harmony imposed by an external creator.
Aristotle, the father of biology, expanded this idea to include the development of organisms and the origins of groups of organisms. To Aristotle, the adult form represented the final goal or telos, and the changes occurring during embryological development represented a striving towards the telos and is dictated by the telos.
Aristotle used this idea to develop a "scale of nature," in which he arranged the natural world on a ladder commencing with inanimate matter to plants, invertebrates, and vertebrates. Among the vertebrates, he placed the fish at the lowest rung of the ladder and humans on the highest rung. This "scale of nature" represents a progression from the most imperfect to the most perfect.
The concepts developed by the Greek philosophers retained their influence well into the 18th century and were nurtured by prominent thinkers such as Goethe (1749-1832), who believed that the origin of each level of organism was based on a fundamental primitive plan—an archetype—from which the more complex features and organisms developed.
Although these naturalistic models of origins have existed for many centuries, only since the work of Charles Darwin (1809-1882) has biological evolution become socially accepted. The ideas propagated by Darwin were totally in conflict with the Christian worldview of his time. The Biblical account of Genesis was considered by Church authorities to be the only correct version of origins and the age of the earth was measured by the number of generations since Adam. In contrast, the Darwinian concept of evolution required millions of years for the gradual change of form and structure required for the transition of one species into another.
The conflict between Christianity and Darwinism centered largely on time and fixity of species. Ironically, Aristotle believed in the fixity of species, and Augustine (AD 345-430) had incorporated this concept into Christian thought. The European worldview in Darwin's time was that God had created unchangeable fixed species in the not-too-distant past.