Sentence:  Therefore , the only conceivable alternatives are those represented , on the one hand , by the two at least apparently self-consistent but <WSD>mutually</WSD> 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:  unable to be both true at the same time