A central feature of the dynamic behavior of classical CAS networks is catalytic closure. This is defined as a state in which every molecular component within the network is formed in endogenous reactions catalyzed by at least one of the network members . Catalytically closed CAS networks are proposed to be capable of reproduction . To attain this state, it was suggested that endogenous catalyzed syntheses within a CAS network generate a gradually increasing repertoire of molecules. Catalytic closure is attained only when the molecular repertoire becomes large enough, estimated to be in the order of at least 106 different molecule types . A serious criticism, doubting the realism of ensemble replicators, was that they suffer from the "paradox of specificity", the harmful effect of side reactions occurring in exceedingly large repertoires . It turns out that the GARD model may offer a resolution of this paradox, showing that reproduction may be attained via repertoire diminution en-route to a reproducing attractor (Figure ).