The process and a simple logic of 'meso'. Emergence and the co-evolution of institutions and group size

'Summing-up' aggregation of micro decisions contrasts with structural emergence in complex systems and evolutionary processes. This paper deals with institutional emergence in the 'evolution of cooperation' framework and focuses on its size dimension. It is argued that some 'meso' (rather than 'macro') level is the proper level of cultural emergence and reproduction. Also Schumpeterian economists have discussed institutions as 'meso' phenomena recently, and Schelling, Axelrod, Arthur, Lindgren, and others have dealt with 'critical masses' of coordinated agents and emergent segregations. However, emergent group size has rarely been explicitly explored so far. In an evolutionary and game-theoretic frame, 'meso' is explained in terms of a sustainably cooperating group smaller than the whole population. Mechanisms such as some monitoring, memory, reputation, and active partner selection loosen the total connectivity of the static and deterministic 'single-shot' logic and thus allow for emergent 'meso' platforms, while expectations 'to meet again' remain sufficiently high. Applications of 'meso-nomia' include the deep structure of 'general trust' and macro-performance in 'smaller' and 'well networked' countries which helps to explain persistent 'varieties of capitalism'.