Sydney Brenner argues that cells and living organisms are good examples of Turing and von Neumann machines (Nature 482, 461; 2012). But the nature of living matter cannot be properly accommodated within such a theoretical framework.

This is because the language that codes machine programs is not compatible with that of the genetic code. Languages controlling Turing and von Neumann machines are formal algorithms, in which syntax determines meaning independently of context. Gene expression depends on environmental context, however, so cannot be similarly treated as a formal language.

Syntax in DNA may convey different and even contradictory meanings, depending on the cellular agents that exploit the coded information according to their respective situations.