About nothing

  title={About nothing},
  author={A. Brower and Mario C. C. Pinna},
In light of recent terminological controversy, this article reviews cladistic conceptions of character states coded as absences, symplesiomorphies, and secondary losses. The first section addresses absence as a question of ontology vs. epistemology. The second and third sections address the evidentiary status of symplesiomorphy in cladistics, the fourth contrasts primitive absence with secondary loss, and the fifth clarifies the meaning of “grouping”. While secondary losses (reversals) are… Expand
Homology and misdirection
Hennig (1966) recognized symplesiomorphies as homologies, and that view is logically correct under the concept of homology (homogeny) prevalent among evolutionists since 1870. Nelson and PlatnickExpand
Homology and synapomorphy‐symplesiomorphy—neither synonymous nor equivalent but different perspectives on the same phenomenon
I, however, do not consider the concept of homology equal or synonymous to that of synapomorphy and symplesiomorphy, as they represent different perspectives on the same phenomenon, i.e. correspondence by common origin. Expand
What is a cladogram and what is not?
The origins and meanings of “cladogram” are reviewed and numerous recent authors treat it as synonymous with “dendrogram” and do not appreciate the particular methodological connotations of the former term. Expand
Patterns of character evolution in phylogenies
The main purpose in this letter is eliminating redundancy and increasing precision in the description of the patterns of character evolution in phylogenies, i.e., apomorphy and plesiomorphy. Expand
Homology assessment in parsimony and model‐based analyses: two sides of the same coin
Although parsimony and model‐based analyses usually achieve concordant topological results, they may generate discordant inferences of character evolution from the same datasets, indicating that method selection has serious implications for evolutionary scenarios and classificatory arrangements. Expand
Assessing similarity: on homology, characters and the need for a semantic approach to non‐evolutionary comparative homology
The problem of homology has been a consistent source of controversy at the heart of systematic biology, as has the step of morphological character analysis in phylogenetics. Based on a clearExpand
Impact of errors on cladistic inference: simulation-based comparison between parsimony and three-taxon analysis
Parsimony is shown to be more efficient with numerous character states (more than four), and 3ta to beMore efficient with binary characters, both methods being equally efficient with four states per character. Expand
Dealing with propositions, not with the characters: the ability of three-taxon statement analysis to recognise groups based solely on ‘reversals’, under the maximum-likelihood criteria
It is demonstrated that groups based solely on putative reversals are always recognisable after maximum-likelihood analysis of three-taxon statement matrices, even without a priori recoding of the putative reversal states as new character states or fractional weighting ofThree- taxon statements. Expand
Analyzing the Impact of Conflictive Dental Characters on the Phylogeny of Octodontoid Rodents
The results indicate that reanalyses of conflictive dental characters, scrutinizing data matrices, are particularly necessary to evaluate the current controversy on the phylogeny of octodontoids. Expand
Experimental systematics: sensitivity of cladistic methods to polarization and character ordering schemes
The results of simulations of the evolution of phenotypic traits under a Brownian motion model are presented to characterize differences in sensitivity between parsimony and 3ta to outgroup branch length, which affects the reliability of ancestral character state estimates, (2) character state ordering scheme, and (3) ingroup branch lengths that reflect the geological age of studied taxa. Expand


Homology and errors
An alternative definition of homology is proposed and primary and secondary homology are defended as realistic representations of discovery procedures in comparative biology, recognizable even in Direct Optimization. Expand
Monophyly, Paraphyly, and Natural Kinds
This essay proposes to conceptualize the hierarchy of higher taxa is terms of a hierarchy of homeostatic property cluster natural kinds in terms of cladistic methods of phylogeny reconstruction. Expand
Congruence and language
Knowledge claims in comparative biology are interpretations/explanations (propositions) of facts. These facts help us to discover the interrelationships amongst taxa and areas. Relationships areExpand
“Pattern cladistics” really means paraphyly
By EWT’s account, furthermore, computer programs used in cladistics depart from Hennig’s original method and are necessarily phenetic. In fact, as I will point out here, EWT’s accusations are merelyExpand
On homology
Homology in cladistics is reviewed. The definition of important terms is explicated in historical context. Homology is not synonymous with synapomorphy: it includes symplesiomorphy, and HennigExpand
Pattern taxonomy
In the course of reacting against Hennig and cladists, Williams, Ebach, and their allies have advanced a variety of remarkable claims, but most are pure fabrications, and some recent papers are devoted to exposing those deceptions. Expand
Ontogeny, Phylogeny, Paleontology, and the Biogenetic Law
The biogenetic law is restated in a falsifiable form: given an ontogenetic character transformation, from a character observed to be more general to a character observation to be less general, the more general character is primitive and the less general advanced. Expand
Logical equivalence between the notions of homology and synapomorphy is reviewed and supported, and a general theoretical solution is proposed to determine evolution of characters with ambiguous distributions, based on the notion of maximization ofHomology propositions. Expand
Logical basis for morphological characters in phylogenetics
Systematists have questioned the distinction between characters and character states and their alignment with the traditional concept of homology. Previous definitions for character and characterExpand
Counterfeit cladistics
Sir, Nixon and Carpenter (in press) correctly point out that symplesiomorphies can be homologies, so that Patterson (1982) was wrong to equate homology with Hennig s (1966) synapomorphy. They do not,Expand