As Maynard-Smith and Szathmáry point out (1999, 137), the social structures we find among humans (and other ‘higher animals’) are woven together by the mutual recognition of selves. The concept of self is a consequence of this, not a precondition of it: we recognize our selves because we recognize others as individuals (Bogdan 2000 and many others).
At the same time, what counts as an individual depends on what we are trying to account for. In classifying life forms, biologists can ‘consider the species as a whole as an individual, ontologically speaking.… Species taxa are individuals in the sense that each species has spatiotemporal unity and historical continuity’ (Mayr 1982, 253). Yet a single living person can equally well be considered as a symbiotic community of cell types and semiotic functions.
An embryo … has a dual inheritance system, one system depending on the copying of DNA base sequences, the other on the copying of states of gene activity [this is how cells are able to differentiate during growth of the embryo even though each carries the entire genome]. There is an obvious analogy between the differentiated cells of an animal body, the various castes in an ant colony, and the different trades and professions in human society. The Israeli biologist, Eva Jablonka, has pointed out that the analogy between an animal body and human society is deeper than just the presence of differentiated parts. Human society also depends on a dual inheritance system, based on DNA and language.— Maynard Smith and Szathmáry (1999, 28-9)
Language is probably the most important medium of cultural “inheritance,” but other kinds of semiosis are involved as well. The continuity of a human society depends on interactions between semiotic processes internal to the body, those internal to the biological species (genetic inheritance), and those which Peirce called ‘external signs’ – including human individuals themselves.