"Society is purely and solely a continual series of exchanges... And the greatest eulogy we can give it, for exchange is an admirable transaction, in which two contracting parties always both gain; consequently, society is an uninterrupted succession of advantages, unceasingly renewed for all its members."
Source : Donna Smallin (2014). “Clear the Clutter, Find Happiness: One-Minute Tips for Decluttering and Refreshing Your Home and Your Life”, p.65, Storey Publishing
Source : William Poundstone (2010). “Fortune's Formula: The Untold Story of the Scientific Betting System That Beat the Casinos and Wall Street”, p.57, Macmillan