Biology and Philosophy

, Volume 6, Issue 3, pp 303–324

Complexity and evolution: What everybody knows

  • Daniel W. McShea

DOI: 10.1007/BF00132234

Cite this article as:
McShea, D.W. Biol Philos (1991) 6: 303. doi:10.1007/BF00132234


The consensus among evolutionists seems to be (and has been for at least a century) that the morphological complexity of organisms increases in evolution, although almost no empirical evidence for such a trend exists. Most studies of complexity have been theoretical, and the few empirical studies have not, with the exception of certain recent ones, been especially rigorous; reviews are presented of both the theoretical and empirical literature. The paucity of evidence raises the question of what sustains the consensus, and a number of suggestions are offered, including the possibility that certain cultural and/or perceptual biases are at work. In addition, a shift in emphasis from theoretical to empirical inquiry is recommended for the study of complexity, and guidelines for future empirical studies are proposed.

Key words

Complexityentropyevolutionevolutionary trendsHerbert Spencerprogress

Copyright information

© Kluwer Academic Publishers 1991

Authors and Affiliations

  • Daniel W. McShea
    • 1
  1. 1.Committee on Evolutionary BiologyUniversity of ChicagoChicagoU.S.A.