A government is the system or group of people governing an organized community, often a state. In the case of its broad associative definition, government normally consists of legislature, executive, and judiciary. Government is a means by which organizational policies are enforced, as well as a mechanism for determining policy. Each government has a kind of constitution, a statement of its governing principles and philosophy. Typically the philosophy chosen is some balance between the principle of individual freedom and the idea of absolute state authority (tyranny). While all types of organizations have governance, the word government is often used more specifically to refer to the approximately 200 independent national governments on Earth, as well as subsidiary organizations. Historically prevalent forms of government include monarchy, aristocracy, timocracy, oligarchy, democracy, theocracy and tyranny. The main aspect of any philosophy of government is how political power is obtained, with the two main forms being electoral contest and hereditary succession. Libertarianism and anarchism are political ideologies that seeks to limit or abolish government, finding government disruptive to self organization and freedom. A government is the system to govern a state or community. The word government derives, ultimately, from the Greek verb κυβερνάω (meaning to steer with gubernaculum (rudder), the metaphorical sense being attested in Plato's Ship of State).