Fisher's Fundamental Theorem of Natural Selection—A Philosophical Analysis

This paper provides a philosophical analysis of the ongoing controversy surrounding R.A. Fisher's famous ‘fundamental theorem’ of natural selection. The difference between the ‘traditional’ and ‘modern’ interpretations of the theorem is explained. I argue that proponents of the modern interpretation have captured Fisher's intended meaning correctly and shown that the theorem is mathematically correct, pace the traditional consensus. However, whether the theorem has any real biological significance remains an unresolved issue. I argue that the answer depends on whether we accept Fisher's non-standard notion of environmental change, on which the theorem rests; arguments for and against this notion are explored. I suggest that there is a close link between Fisher's fundamental theorem and the modern ‘gene's eye’ view of evolution. 1. Introduction2. What Does the Fundamental Theorem Say?3. Key Concepts Explained4. Alleged Significance of the FTNS5. Traditional versus Modern Interpretations of the FTNS6. The Modern Interpretation Illustrated7. Fisher's Concept of ‘Environmental Change’8. Causality and the Modern Interpretation9. The Significance of the FTNS Re-consideredAppendix