The formal norm for human beings
In the text Psychoanalysis and Philosophy (1993), Castoriadis calls the subjectivity characteristic of autonomy - a reflective and deliberate subjectivity - "the formal norm for human beings" (The Castoriadis Reader, trans/ed. D.A. Curtis, Blackwell 1997). This statement of a certain philosophical anthropology, indicates that autonomy is seen by Castoriadis to be the realization of human nature; autonomy is the cultural life form that allows human beings to flourish. As such, this passage goes against the interpretation of autonomy as something that we invented, and then kept striving for because we liked it - i.e. mere perspecitivsm. See earlier discussions on this topic here - post called Three levels of autonomy ...
I furthermore have found more reasons to relativize the stark opposition of heteronomy and autonomy (confer discussion opened by Suzi here), in that traditional "heteronomous" societies are in many ways reproducing themselves by stories whose meaning and significations are rather open-ended. Cf. myths, which are rather more stimulative to the creative imagination than atheist imagery. I think CC might agree on this.