René Girard, answered from the texts and cited to the page.
When mimetic rivalry spreads through a community, distinctions collapse — the differences that hold a society apart dissolve into a war of each against all, a crisis of undifferentiation.1 Such a crisis cannot be argued to an end; it ends only when the violence, by the same mimetic contagion that spread it, converges on a single victim.23 All against one, in place of all against all.
The victim is chosen not for guilt but for availability and for the marks that set them slightly apart — the stranger, the king, the cripple, the outsider. The community kills or expels this one, and the peace that follows, sudden and total, seems miraculous, seems to come from the victim, who is therefore remembered as both the cause of the plague and the bringer of peace: monster and god.
This is the origin of the sacred. Ritual re-enacts the killing to renew the peace; prohibition forbids the rivalries that led to crisis; myth tells the story from the killers' side, and so remembers the victim as guilty. Religion, culture, the very institutions that hold violence in check, are founded on a murder they cannot afford to remember as murder.45
Since the power of mimetic attraction multiplies with the number of those polarized, it is inevitable that at one moment the entire community will find itself unified against a single individual. Conflictual mimesis therefore creates a de facto allegiance against a common enemy, such that the conclusion of the crisis is nothing other than the reconciliation of the community.Things Hidden Since the Foundation of the World, p. 39
But the observation of religious systems forces us to conclude (1) that the mimetic crisis always occurs, (2) that the banding together of all against a single victim is the normal resolution at the level of culture, and (3) that it is furthermore the normative resolution, because all the rules of culture stem from it. J.-M. O.: All of them? R.Things Hidden Since the Foundation of the World, pp. 39–40
It entails the scapegoating of a victim by a collective. Can you say how you went from mimetic desire to your theory that the so-called "scapegoat mechanism" lies at the origins of human societies? Girard: Mimetic desire, when it spreads, spreads violence with itself, conflict among people, rivalry, because it means that people all desire the same thing. Now, how far can that go?Conversations with René Girard, pp. 110–111
Already, the clumping of tensions around scapegoats that are less and less partial makes one think of the birth of tornadoes or of lumps in a composite mixture. But, what's more, in the "designation" of the collective victim, we now see chance at work—the same chance that physicists, paleontologists, and others find so interesting. And I suspect that the question of democracy must not be far behind.When These Things Begin, pp. 32–33
These themes represent what mythology is unable to conceive rationally, the undifferentiated reciprocity of mimetic conflict.The Girard Reader, p. 12
The scapegoat mechanism is Girard's central anthropological claim and his most contested. It extends Durkheim (the sacred is the collective) and Freud (culture begins in a founding murder) while correcting both, and it has proved genuinely powerful for reading persecution texts, myths, and witch-hunts. The objections are serious: anthropologists such as Walter Burkert locate the origin in ritual and the hunt rather than in a single spontaneous lynching; others deny that one mechanism can explain the enormous diversity of religious forms and charge that the theory absorbs every counterexample by treating the absence of visible victimage as proof of a successful, and therefore hidden, mechanism. Whether the theory is a falsifiable scientific hypothesis or a totalizing hermeneutic is the standing dispute.