Sentence:  The latter assumption is not entirely without justification; for if one defines "history" as the <WSD>sum-total</WSD> of human events, and “society” as the <WSD>sum-total</WSD> of myriads of human beings and their activities, then one may claim that, insofar as they both designate <WSD>sum-totals</WSD>, the two terms are interchangeable. 
Meaning of the word marked with <WSD> tags:  Entirety.