Another advantage is the possibility of cooperation, the division of labor. Each member learns only part of the accumulated knowledge. So he (or she) has to learn during less time and so can be productive for a greater portion of his life span. He works using the part of the total existing knowledge he has learned, and supplies the other members with the results of his work. The society facilitates this exchange by standardizing measures of time, weight, length, and so on, and issuing money. This allows each member to reach its objectives much easier than without a society; it permits to have a better standard of living. For instance most of us do not have the knowledge of an architect or the machines of a construction company. So we let them build our house instead of building it ourselves. Finally, within a society, by cooperation, the common defense is much easier. The society is very much stronger than individual members.