In the early 20th century British mathematician and philosopher Bertrand Russell, along with British mathematician and philosopher Alfred North Whitehead, attempted to demonstrate that mathematics and numbers can be understood as groups of concepts, or classes. Russell and Whitehead tried to show that mathematics is closely related to logic and, in turn, that ordinary sentences can be logically analyzed using mathematical symbols for words and phrases. This idea resulted in a new symbolic language, used by Russell in a field he termed philosophical logic, in which philosophical propositions were reformulated and examined according to his symbolic logic.