Bedau, Mark A., John S. McCaskill, Norman H. Packard, and Steen Rasmussen. “A Discussion of the Use of Artificial Life Models to Evaluate Gould’s Hypothesis about Progress in Evolution.” (2000): 248-252.
Stephen Gould has introduced the hypothesis that progress in evolutionary history is due to contingency. Daniel Dennett has further suggested that this hypothesis could be confirmed or denied by artificial life models, in which multiple evolutionary histories can be produced and the role of contingency thus evaluated. While existing models do not allow for this evaluation, Calabretta et al. (1998) suggest a general form to be used in developing artificial life models to answer questions about biology. Using this form, a model is outlined which may be able to test this hypothesis.