It is difficult for any scholar to construct a portrait of Jesus that can be considered historically valid beyond the basic elements of his life. As a result, W.R. Herzog has stated that: "What we call the historical Jesus is the composite of the recoverable bits and pieces of historical information and speculation about him that we assemble, construct, and reconstruct. For this reason, the historical Jesus is, in Meier's words, 'a modern abstraction and construct.'" According to James Dunn, "the "historical Jesus" is properly speaking a nineteenth and twentieth-century construction, "not" Jesus back then, and "not" a figure in history" (emphasis original). Dunn further explains "the facts are not to be identified as data; they are always an "interpretation" of the data. For example, scholars Chris Keith and Anthony Le Donne point out that under Bultmann and form criticism in the early and mid-twentieth century, Jesus was seen as historically "authentic" only where he was dissimilar from Judaism, whereas, in contemporary studies since the late twentieth, there is near unanimous agreement that Jesus must be understood within the context of first century Judaism.