Sentence:  If Bultmann 's own definition of myth is strictly adhered to ( and it is interesting that this is almost never done by those who make such pronouncements ) , the evidence <WSD>is</WSD> overwhelming that he does not at all exaggerate the extent to which the mythological concepts of traditional theology have become incredible and irrelevant . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)