Published online by Cambridge University Press: 01 January 2022
Thomas Polger and Lawrence Shapiro claim that unlike human-made artifacts cases of multiple realization in naturally occurring systems are uncommon. Drawing on cases from systems biology, I argue that multiple realization in naturally occurring systems is not as uncommon as Polger and Shapiro initially thought. The relevant cases, which I draw from systems biology, involve generalizable design principles called network motifs, which recur in different organisms and species and perform specific functions. I show that network motifs with entirely different underlying causal structures can perform the same function of interest. The article also considers the scope problem of multiple realization.
I am grateful to a number of friends and colleagues for feedback on early drafts of this work, including Malcolm Forster, Ying Liu, and Jiji Zhang. I am also grateful to two anonymous referees, who helped me significantly strengthen some arguments of the article, and two friends, Carl Brusse and Caitrin Donovan, who offered excellent language assistance. This study was funded by the Humanities and Social Sciences Fund for Early-Career Scholars provided by the Ministry of Education, China (grant 0300 270 0002). The author declares that he or she has no conflict of interest.