Human belief formation is homologous genetic recombination via horizontal gene transfer in prokaryotes. Just as a prokaryote can incorporate into its genome DNA from its environment via transformation, or from viral infection via transduction, or from other prokaryotes via conjugation, so can a human mind freely take in and integrate into its belief systems ideas from multiple sources. In both cases, rapid responses to changing environments are made possible. As expression of newly incorporated genes may modify the phenome and behavior of a prokaryote, so may a newly incorporated idea express as the altered personal appearance, possessions, or behavior of the believer, for the good or ill of the individual in both cases.

A disanalogy emerges when considering reproduction. While the survival to cell division of the prokaryote transmits the modified genome to its descendant, the survival of the idea is independent of the survival of its biological host and only requires memetic replication via mimicking of expression or symbolic communication, which may be mediated by inorganic recording and/or broadcast media.

That difference in unmediated versus mediated replication is a danger to mimetic hosts, who may be destroyed by the beliefs they carry and yet still ultimately help transmit to destroy others, as they need not survive to propagate the ideas they express. Ultimately, bad ideas will die if all mimetic hosts die but, given mediated replication, it becomes a race between biological reproduction of mimetic hosts and the ideas that help or hinder their survival.

What is perhaps wanting is a homology to eukaryotic reproduction, where genetic recombination is much more controlled. Chance mutations aside, genetic changes in eukaryotes occur only during genetic recombination in sexual reproduction. This safeguards the host eukaryote against deleterious genetic changes during its lifetime (though also preventing adaptive changes) but has the advantage of always generating diversity at each generation, whereas prokaryotic reproduction usually produces exact genetic clones. That appears to be a successful strategy for generating massive quantity, but doesn’t support the kind of preservation-of-what-works combined with seeing-what-might-work-better that generates the proliferating wondrous complexity of eukaryotic life.

So perhaps what is needed in mimetic replication is the evolution of a latching mechanism similar to sexual reproduction. That is, a filter that prevents the replication of ideas that kill their hosts or lead to the extinction of the population. In sexual reproduction, genes lethal to the host don’t get widely propagated because the host doesn’t survive to reproduce and pass them on. (Post-reproductive degenerative disease and senescence itself obviously still get by this filter.)