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 <WSD>speculating</WSD> on the nature of things . 
Meaning of the word marked with <WSD> tags:  to believe especially on uncertain or tentative grounds