"A salt is any substance caused by the reaction of an acid and a base. For a long time, the existence of acids and bases had been known but little understood. Acids were sour tasting and had the ability to dissolve metal. Bases felt soapy. But acids and bases have a natural affinity for each other because nature seeks completion and, as with all good couples, acids and bases make each other more complete. Acids search for an electron that they lack, and bases try to shed one. Together they make a well-balanced compound, salt. In common salt the base, or electron donor, is sodium, and the acid, or electron recipient, is chloride.
It turns out that salt was a microcosm for one of the oldest concepts of nature and the order of the universe. From the fourth century B.C. Chinese belief in the forces of yin and yang, to most of the world’s religions, to modern science, to the basic principles of cooking, there has always been a belief that two opposing forces find completion – one receiving a missing part, and the other shedding an extra one.
- Salt, A World History, by Mark Kurlansky.