Phylogenetic series - Philosophical Concept | Alexandria
Phylogenetic series, often envisioned as a linear progression of evolutionary stages, represent a historical construction attempting to depict the sequential development of organisms through time, yet obscuring the complex, branching nature of evolution. The Scala Naturae, the Great Chain of Being, and orthogenesis are related, if often misunderstood, concepts. Do these concepts reveal nature's inherent order or simply humanity's need for hierarchical storytelling?
The concept of sequential life forms traces back to antiquity. Aristotle, in his History of Animals (4th century BCE), described a hierarchical "ladder of life," arranging organisms from simple to complex, unwittingly setting the stage for later interpretations of evolution as a linear climb. This notion resonated through the medieval period and found expression in the Scala Naturae, a concept popularized by thinkers such as Plotinus. These early attempts were based on observation and philosophical reasoning rather than modern evolutionary biology. The scientific revolution, driven by icons such as Nicolaus Copernicus, Galileo Galilei and, later, Charles Darwin, directly challenged these previously held notions of a linear progression of life. These intellectual transformations suggest that human understanding is always subject to revision.
During the 19th century, with the rise of evolutionary thought, many scientists, including Ernst Haeckel, interpreted evolution as a directed process, envisioning phylogenetic series as a reflection of inherent progress or orthogenesis. Haeckel's "biogenetic law," claiming that ontogeny recapitulates phylogeny, was a powerful, if ultimately flawed, illustration of this perspective. However, the work of Charles Darwin and subsequent developments in genetics and molecular biology demonstrated that evolution is not a simple linear progression but rather a branching, diversifying process shaped by natural selection, genetic drift and other mechanisms. Despite its historical importance, contemporary evolutionary biology rejects the idea of a linear phylogenetic series as a primary representation of evolutionary relationships, favoring instead the branching diagrams known as phylogenetic trees. Nevertheless, remnants of the concept persist, sometimes subtly influencing narratives of progress or complexity in evolutionary history. This transition prompts us to question how our cognitive biases shape scientific understanding.
The notion of a phylogenetic series, though largely superseded by modern phylogenetic methods, continues to intrigue, serving as a reminder of how our understanding of nature has evolved. Even though phylogenetic trees offer a more accurate representation of evolutionary relationships, the simple allure of the linear series endures in popular imagination, underscoring the human tendency to seek simple, ordered narratives. This continuing mystique compels us to ask: how do we reconcile the messiness of evolution with our innate desire for order and straightforward narratives?