Sentence:  But to say that at a moment in history something <WSD>is</WSD> new is not necessarily to say that it is modern ; and for this statement the best evidence comes within the five years following the publication of Utopia , when Martin Luther elaborates a new perception of the nature of the Divine 's encounter with man . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)