Criterion of dissimilarity

The criterion of dissimilarity (also called criterion of discontinuity) is used in Biblical criticism to determine if a statement attributed to Jesus may be authentic. It is often used as a shorthand for the criterion of double dissimilarity. The criterion states that if a saying attributed to Jesus is dissimilar to the Jewish traditions of his time and also from the early Church that followed him, it is likely to be authentic.

This criterion was introduced by Ernst Käsemann who in 1953 started the second quest for the historical Jesus. Käsemann writes:

[T]here is an almost complete lack of satisfactory and water-tight criteria for this material. In only one case do we have more or less safe ground under our feet: when there are no grounds either for deriving a tradition from Judaism or for ascribing it to primitive Christianity, and especially when Jewish Christianity has mitigated or modified the received tradition, as having been too bold for its taste. (Käsemann, Essays on New Testament Themes, p. 37)

In other words, the criterion postulates that traditions about Jesus derive from (only) three sources: extrapolation from earlier Jewish traditions, revisionism by the early Christian Church, and true historical accounts of Jesus's ministry. If some tradition cannot be adequately explained by extrapolation nor by revisionism, then it must necessarily be a trace of the historical Jesus.

The criterion has received criticism for leading to reconstructions of Jesus as being in implausible discontinuity with the early Jewish traditions that preceded him and the early Christian traditions that followed from him. One such critic writes: "The problem of the Criterion of Double Dissimilarity is that the more we know about early Jewish traditions and the more we know about early Christian post-Easter traditions, the less space there is for a reconstruction of the authentic sayings of Jesus, as by definition they have to differ from early Jewish and early Christian traditions. Therefore, in the end, no trace of a historical Jesus remains."

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