Sentence:  I maintain, however, on the one <WSD>hand</WSD>, that there are few occasions upon which large bodies of men, such as politics is concerned with, can rise above selfishness, while, on the other <WSD>hand</WSD>, there are a very great many circumstances in which populations will fall below selfishness, if selfishness is interpreted as enlightened self-interest. 
Meaning of the word marked with <WSD> tags:  A side; part, camp; direction, either right or left.