TRIVIAL VERSUS NON-TRIVIAL REPLICATORS. “Although von Neumann automata are self-replicators, their mode of replication is non-trivial in a fundamental, logical sense, and should be distinguished from trivial replicators such as crystals, viruses, computer viruses, non-enzymatic template replicators, lipid composomes and Penrose blocks.”
http://rsif.royalsocietypublishing.org/content/10/79/20120869