Sentence:  Therefore , the only conceivable alternatives <WSD>are</WSD> those represented , on the one hand , by the two at least apparently self-consistent but mutually exclusive positions of Buri and Barth and , on the other hand , by the third but really pseudo position ( analogous to a round square ) of Bultmann . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)