While I do not think they pan out in as neat a historiographical way as he thought, these finely tuned typological distinctions offered by Gavin Langmuir suss out assertions of in-group animus for outgroups.
Langmuir makes these distinctions about intergroup animus. They are “formal characteristics intrinsic to the assertions—or vehicles of communication—themselves.”
Realistic assertions about outgroups are propositions that utilize the information available about an outgroup and are based on the same assumptions about the nature of groups and the effect of membership on individuals as those used to understand the ingroup and its reference groups and their members.
Xenophobic assertions are propositions that grammatically attribute a socially menacing conduct to an outgroup and all its members but are empirically based only on the conduct of a historical minority of the members; they neglect other, unthreatening, characteristics of the outgroup; and they do not acknowledge that there are great differences between the individuals who compose the outgroup as there are between the individuals who compose the ingroup.
Chimerical assertions are propositions that grammatically attribute with certitude to an outgroup and all its members characteristics that have never been empirically observed.
(Towards a Definition of Anti-Semitism, 328).
Chimerical assertions include “fantasies, figments of the imagination, monsters that, although dressed syntactically in the clothes of real humans, have never been seen and are projections of mental processes unconnected with the real people of the outgroup. Chimerical assertions have no “kernel of truth”