Sentence:  Yes , he believed that the Jews were `` enemies of the Reich '' , and such a belief is , of course , typical of `` patriotic '' anti-Semites ; but he believed in the Jew as enemy in a kind of abstract , theological way , like a member of a cult speculating on the <WSD>nature</WSD> of things . 
Meaning of the word marked with <WSD> tags:  the essential qualities or characteristics by which something is recognized