What would be conserved if `the tape were played twice'?

W. Fontana and L. W. Buss

We develop an abstract chemistry, implemented in a -calculus based modelling platform, and argue that the following features are generic to this particular abstraction of chemistry, hence would be expected to reappear if 'the tape were played twice': (i) hypercycles of self-reproducing objects arise, (ii) if self-replication is inhibited, self-maintaining organizations arise, and (iii) self-maintaining organizations, once established, can combine into higher-order self-maintaining organizations.