Sentence:  It <WSD>is</WSD> idle to ask why we are no longer disturbed if somebody , professing the deepest piety , decides anew that it is of no importance whether or not Christ transformed the water into wine at eleven A. M. on the third of August , A. D. 32 . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)