Testability and the Refutation and Corroboration of Cladistic Hypotheses

Area of Science:

• Evolutionary Biology
• Philosophy of Science

Background:

• Phylogenetic inference, the process of reconstructing species evolutionary history, is increasingly influenced by two distinct epistemologies: refutationism and verificationism.
• These differing philosophical underpinnings, particularly the emphasis on refutation in cladistics, present a fundamental divergence in scientific practice.

Purpose of the Study:

• To explore the refutationist nature of cladistics through the lens of Popperian testability.
• To understand the implications of this epistemological stance for phylogenetic inference and predict potential shifts in the field.

Main Methods:

• Analysis of phylogenetic inference methodologies using Popperian concepts of testability, refutation, and corroboration.
• Examination of the logical relationship between phylogenetic hypotheses (cladograms), evidence (synapomorphy), and background knowledge (descent with modification).

Main Results:

• Phylogenetic hypotheses must be improbable given background knowledge to be testable and potentially corroborated.
• Key cladistic principles like minimizing ad hoc hypotheses, maximizing empirical content, and utilizing total evidence align with refutationist principles.
• Differential character weighting is deemed incompatible with testability, and testability itself does not guarantee accuracy, only falsifiability.

Conclusions:

• The refutationist approach, grounded in Popperian testability, provides a coherent framework for understanding current cladistic practices.
• A paradigm shift towards refutationism in phylogenetic inference appears likely, moving away from verificationist goals of absolute truth.
• The focus remains on rigorous testing and corroboration of hypotheses rather than definitive accuracy.