Sentence:  [P]hilosophers of the time [early 20th century] were primarily concerned with epistemology and the foundations of the sciences; they often spoke as if we were separated from the real world by a screen of "representations" or "sense-data"; they tended to regard our approach to the world as one of <WSD>disinterested</WSD> observation. 
Meaning of the word marked with <WSD> tags:  Having no stake or interest in the outcome; free of bias, impartial. (from 17th c.)