[this space is itching to be filled with more ideas, collective or otherwise...]
It should be noted that a CollectiveIdea, once formed, is almost impossible to unform, deform, or reform. TheCollective provides amazing self-reinforcing strength that repels, rejects and represses alternative concepts. After all, since the CollectiveIdea filters into the minds of the individual agents, the agents themselves cannot formulate a new idea because they are so attached to the old one. Also, GroupThink pervades TheCollective and squashes dissenting views. -- SunirShah
[This has been lifted in part from Wiki:CollectiveIdea]
More on structuralism http://www.classics.cam.ac.uk/Faculty/structuralism.html
--- Thomas Kuhn's observation that lots gets done as a result of consensus has been mentioned elsewhere, but this idea should be recognized as part of a more radical notion of collective intelligence and reason itself. Jurgen Habermas observes that paradigms or still waters of logic are indistinguishable from Reason itself, since communication is what we mean by Reason (logic being a particularly efficient variety of communication, except where it fails to inspire.)Actually, Habermas calls it "communicative action" and far from being a war of ideas, he views human reason as a unified organism. "In our everyday knowledge of how language is properly used we find a common ground among all creatures with a human face." The ebb and flow of cultural dominants or paradigms leads to what...? Habermas believes it is transcendence of cultural and egotistical bias.
All this jabber is by way of situating the notion of a CollectiveIdea as a belief in Universalism. Can it/should it be resisted? Foucault wouldn't disagree that convergent communication is a hallmark of reason, he would deride culturally agnostic "reason" as a tool of oppression. As post-modernism in general argues, self-referential systems, however reasonable are themselves fictional narratives, frameworks that include some limit or boundary by darkening or suppressing some conceptual opposite. This is the truth claim of moral relativism. Ironically, philosophers situated in American institutions of learning seem to react to the fascist potential of the corporate academies that employ them, whereas philosophers in the rough who have experienced actual fascism, like Habermas, react to their personal experience and need to believe in transcendant human faculties of reason.
===== Neuropsychology provides the next interesting link in this chain. Antonio Damasio's book "Descartes Error" is an excellent source of information on how reason and emotion are not and never could be separated. Artificial intelligence provides concrete examples of how sign systems and logical operations cannot correct for errors. Perhaps more intriguing than philosophical question of whether Reason and Communication are transcendent is DaMassio? discussion of how mind is not separate from body. This provides a framework for the emergence and shifting of CollectiveIdeas quite different from the "pure thought" or "Cogito Ergo Sum" sort.