Evolution Is Not a Necessary Assumption of Cladistics

Area of Science:

• Systematic biology
• Phylogenetic analysis
• Philosophy of science

Background:

• Ongoing debate exists regarding the foundational axioms necessary for cladistics.
• Previous emphasis by authors highlighted that descent with modification is not a prerequisite for cladistics.
• Confusion persists about the essential background knowledge underpinning cladistic methodology.

Purpose of the Study:

• To review the fundamental axioms required to justify cladistics.
• To clarify the necessary and sufficient background knowledge for cladistic methods.
• To strengthen the philosophical justification for cladistics by examining its relationship with evolutionary theory.

Main Methods:

• Review of three core axioms: discoverability of characters, hierarchy, and parsimony.
• Analysis of the sufficiency of the evolution assumption for justifying cladistics.
• Comparison of cladistics with competing methods like maximum likelihood under the evolution assumption.

Main Results:

• The axioms of discoverability, hierarchy, and parsimony are necessary to justify cladistics.
• While the assumption of evolution is sufficient for cladistics, it also justifies alternative methods.
• Purging the assumption of descent with modification strengthens the philosophical support for cladistics.

Conclusions:

• Cladistics can be justified independently of the assumption of descent with modification.
• The philosophical underpinnings of cladistics are more robust when focusing on its inherent axioms.
• Evolutionary assumption sufficiency for cladistics also supports competing phylogenetic methods.