Functions and health at the interface of biology and technology

Synthetic biology promises to eliminate the distinction between biology and engineering by delivering a philosophically interesting new kind of entity: a biological organism that is wholly designed and constructed by humans. The possibility of such organisms raises interesting questions in three domains: the analysis of (1) biological functions, (2) engineering functions, and (3) health and disease. This paper identifies and systematically answers these questions. This does not only establish how we should think about functions and health and disease in synthetic biological organisms, but it also reveals insights that are of broader relevance: (1) aetiological accounts of biological function need to omit or reinterpret reference to natural selection. This results in complete continuity between aetiological analyses of function in engineering and philosophy; (2) considering synthetic biology prompts interesting further questions about heritability, ancestry, and biological individuals; and (3) accounts of disease as biological dysfunction do not straightforwardly map onto our intuitive health and disease judgments regarding non-human animals. In response to the latter point I examine three possible avenues, and tentatively defend one on behalf of the ‘disease as dysfunction’ theorist.