Defined in 1872: “The ontogeny of every organism repeats itself in brief … it’s phylogeny, i.e. the individual development of every organism … repeats approximately the development of its race.” (OED) In other words ontogeny generally recapitulates phylogeny, a principle that embraces both the evolution of species in the biosphere and of civilizations in the noosphere. However, if ontogeny always recapitulated phylogeny, no new species or civilizations could ever appear. As human beings we go to school to learn what the culture we were born into wants us to learn, being thoroughly conditioned in the ways of the culture by the time we are adolescents.
For new species and civilizations to appear, individuals need to emerge whose ontogeny does not reach maturity, in terms of the race, but takes a radically new change of direction when young through a process of pædomorphosis. Of course, this is not easy for those individuals, who might appear as freaks to the dominant race. For instance, if an albino is born into a tribe of antelopes, it will most probably be expelled from the group. It is only when a critical mass of individuals gather together that a new species or civilization can establish itself. That, essentially, is what needs to happen if the children born since the beginning of this millennium are to have any chance of growing old enough to have children of their own.
Greek on, genitive ontos, from ont-, stem of present participle einai ‘to be’, and geneia ‘origin’, from genes ‘born’.