Evolutionary contingency as non-trivial objective probability: Biological evitability and evolutionary trajectories

Area of Science:

• Philosophy of Science
• Evolutionary Biology

Background:

• Existing theories of evolutionary contingency often focus on causal structures like path-dependence.
• These accounts may fail to incorporate the crucial concept of biological evitability, i.e., whether evolutionary outcomes could have differed.
• Some current frameworks allow for outcomes to be both contingent and inevitable simultaneously.

Purpose of the Study:

• To critique existing accounts of evolutionary contingency for omitting biological evitability.
• To introduce the concept of trajectory propensity to explain why causal structures alone may not determine evolutionary outcomes.
• To propose a novel, outcome-based definition of evolutionary contingency.

Main Methods:

• Conceptual analysis of existing contingency theories.
• Development of the concept of trajectory propensity.
• Formulation of a new definition based on objective probability within a modal range.

Main Results:

• Identified a theoretical gap in current evolutionary contingency models concerning biological evitability.
• Demonstrated that causal structures alone do not always determine the evitability of evolutionary forms.
• Proposed a novel definition of evolutionary contingency as non-trivial objective probability.

Conclusions:

• A robust account of evolutionary contingency must include biological evitability.
• Trajectory propensity offers a new lens for understanding evolutionary pathways.
• The proposed outcome-based, probabilistic account provides a more comprehensive framework for evolutionary contingency.