The term 'chimeria' comes from Langmuir and is useful for identifying beliefs that are purely delusional, rather than stereotypes or xenophobias that are developed by taking a 'kernel of truth' then exaggerating and distorting it. 'Chimeric' beliefs portray Jews as physical embodiments of Satan, and as a conspiratorial force of darkness that plots world domination. This, in turn, gives the antisemite a Messianic mission of redemption. Thus, as Saul Friedlander argues, Nazi antisemitism has to be understood as 'redemptive': a pseudo-religion.
So far so good, but what are the limits of the concept? I would identify two major ones. Firstly, 'chimeria' only really tells us about the Nazi "true believers", such as Hitler and Streicher. There is no conclusive evidence that the bulk of the Nazi Party's membership believed in Streicher's wild imaginings. Secondly, antisemitic beliefs that build on stereotypes, or which are used to disguise instrumental motives, can be just as genocidal in their effects. Infact, beliefs which can point to a "kernel of truth" (no matter how exaggerated or distorted) are more likely to convince waverers, so may be more useful in a radicalization of policy setting such as Germany in 1939-42. It would be unwise to assume that only "true believers" can participate in genocide. Indeed, such an assumption would take us dangerously close to Goldhagen territory.
For this reason, I would prefer the concept that I discussed in Part 3 of this series, namely Pollution. The advantage of Pollution over Chimeria is that Pollution can have stereotypical or chimeric contents. Pollution helps us to explain how a 'reality-based' concept such as fear of disease or anger at defeat in warfare (the mood of 1918) can be exploited to generate entirely chimeric beliefs. For example, the belief that Bolshevism has some Jewish members is 'reality-based' because some revolutionaries were secularized Jews, but the belief that it was a Jewish conspiracy against gentiles is chimeric because these Jews were not acting from religious or cultural motivations but from political ideas that they shared with their gentile partners.
I would therefore argue that, by separating Chimeria from any "kernel of truth", Langmuir misses the methodology of Nazism, which is to create chimeric beliefs from perverse readings of empirical observations. Delusions are created by converting reality into fantasy, not by generating fantasy entirely independently of real circumstances.