"Of course this depends on the definition of anarchism. This term is quite difficult to pin down, because it has been used to describe many different, and often contradictory, proposed social orders, as well as the movements dedicated to achieving them. The definition of anarchy I use here is systematic opposition to the modern state. “State” is also difficult to define, but a modification of Weber’s conception—the state is the organization that possesses a monopoly on the creation and enforcement of social rules—strikes a good balance between breadth and precision. Political thinkers across the millennia discuss the nature and purpose of government. But it is important to note that Roman jurists, medieval Schoolmen, and philosophers of the Scottish Enlightenment based their political commentary on observations of quite different institutional landscapes. The institutions these writers lived under varied so greatly that we would lose more than we would gain were we to force them all into a single concept. In fact, the term “the state” as applied to a unitary, corporate organization that governs a territory probably originates with Machiavelli in the 16th century. Accordingly, the state should not be equated with formal governance institutions, nor public authority per se.
So to make a complicated matter as simple as possible, an anarchist is somebody who regards the existing, post-Westphalian form of the state as illegitimate. This does not commit the anarchist to any particular course of political action. An anarchist need not be a revolutionary, for example. Nor does it mean the anarchist is opposed to all forms of rules and hierarchies. Anarchists frequently make a distinction between government and governance. All human societies need the latter, both as a means of checking the passions and inculcating virtuous habits. But the former is simply one way of achieving the latter, and historically considered, a relatively young and untested one at that."