So it's probable that we could feel comfortable in communities of this size. About 500 individuals form the smallest possible genetic pool of the species Homo sapiens. It corresponds to the inhabitants of typical older urban neighbourhoods in a lot of countries, to an infantry battalion, to the capacity of a larger hall, to the size of a medium enterprise, to a medium-sized school, etc. The reasons are not purely genetic or traditional. The number of 500 persons permits a minimal diversity of age, sex, interests, a basic division of work.
Age groups are large enough for social interaction and even endogamy is possible.
It's typical for most of the alternative and utopian theorists that they conceive their basic communities from an administrative or purely ecological or technical point of view. Fourier's 'phalansteres' are little universes containing all human passions and occupations. Most modern utopias are in fact totalitarian, mono-cultural models organised around work and education. Most modern utopias are in fact totalitarian, mono-cultural models organised around work and education. Reason, practicability, harmony, non-violence, ecology, economic efficiency, morality, all are central motivations.