Sentence:  We have not the leisure , or the patience , or the skill , to comprehend what was working in the mind and heart of a then recent graduate from the Harvard Divinity School who would muster the audacity to contradict his most formidable instructor , the majesterial Andrews Norton , by saying that , while he believed Jesus `` like other religious teachers '' , worked miracles , `` I see not how a miracle <WSD>proves</WSD> a doctrine '' . 
Meaning of the word marked with <WSD> tags:  establish the validity of something, as by an example, explanation or experiment