Sentence:  Hereby , the external object viewed by the eyes <WSD>remains</WSD> the thing that is seen , not the retinal image , the purpose of which would be to achieve perceptive cooperation by stirring sympathetic impulses in the other sensory centers , motor tensions , associated word symbols , and consciousness . 
Meaning of the word marked with <WSD> tags:  be left; of persons, questions, problems, results, evidence, etc.