An understanding among individuals that membership in a jurisdiction or community requires more than a passive acceptance of the rights of that membership. It goes beyond paying taxes, voting or obeying the law. Thus, active citizenship implies an acceptance of responsibilities to the collective good as well as individual rights. An active citizen is one who has developed or is developing the capacity to engage in public work to solve common problems. This public work involves both practical effort and participation in decision-making about these problems. Active citizens extend due consideration to non-citizens and non-human nature, as well as to other citizens. As an idea, active citizenship is crucial to sustainability in practice.