Traditionally, anarchism is defined as the political philosophy advocating a stateless society. The majority of anarchists are anti-statist ensuring that they presume that anarchism is thoroughly opposed to the existence of a state. Philosophically, there are vague and questionable elements to this definition and conception of anarchism.
We have not been sufficiently clear as to what is being opposed. Is it though the very concept of the state or actually existing states that is being opposed? This distinction is essential for a rigorous debate about the virtues of anarchism. The first disjunct corresponds to a view called a priori anarchism. Essentially, it holds that it is an a priori fact that states are morally unjustifiable entities. Making this statement clearer, all possibly existing states are morally unjustified.
The best argument for this view is an argument made by Robert Paul Wolff in his book In Defense of Anarchism. Wolff argues that it is inconsistent with a persons ability to exercise their free will and yet be under the authority of a supreme authority. The concept of sovereignty is that of having supreme authority over its actions. So the state must be a body that has supreme authority over its subjects. Otherwise the state wouldn’t exist as the entity would not have a key property that states must have, sovereignty. Therefore, it is unjustifiable that a state exist while people are able to exercise the autonomy necessary for them to be moral agents, as to be a moral agent you need free will.
It is clear that Wolff is objecting to an abstract notion of what the state is. All possible states that can exist are under consideration. Even if every state we see and live in today was as generous in allowing citizens to exercise their liberty as Santa Claus is in giving presents to children at Christmas, it would not make the slightest difference to the truth or falsity of Wolff’s argument.
Not all anarchists are philosophically minded though. Even those that are may not be sophisticated users of philosophical argumentation. This gives us a clue that not all anarchists are in fact a priori anarchists. If they are, it indicates they do not have sufficient logical justification for holding that view. I’m not saying that no justification exists for a priori anarchism, only that some anarchists themselves don’t have it.
Most anarchists justify their philosophy empirically by explaining how undesirable social, political and economic phenomena have been caused because of the existence of the state. Market anarchists of the Mutualist sort, for instance, argue that state interference in the market, or elsewhere for that matter, leads to undesirable effects that allow inequalities to foster both socially, politically and economically. It is via a truly free market that individuals can be liberated to live in accordance to their own desires and freedoms.
Notice though that these are empirical statements about the world around us. We should, in theory, be able to test whether the market anarchists are right by simply forming a free market as they envisage it and see whether what happens conforms to their predictions. Why does this matter? For these types of arguments are not a priori arguments. They are a posteriori arguments. In other words, these anarchists cannot immediately state that all states are morally unjustifiable. Why? Because they haven’t considered every possible state that could exist, only ones that actually have existed in the concrete world.
It is here that the debate can get really interesting, but in a bad way. A market anarchist might say that their argument in favour of truly freed markets isn’t an a posteriori one, but an a priori one. The same can apply to anarcho-communists who wish to abolish the market system, abolish private property and abolish all unjust hierarchies. Full communists may argue for their position as a philosophical rationalist like René Descartes would do, rather than a philosophical empiricist like John Locke.
The market anarchist effectively would be arguing a priori, i.e. without any recourse to the way the world works, that markets work and that they promote liberty better than any other system, or are even necessary for the promotion of freedom. It’s not difficult for a philosopher, or any rational person, to see how untenable a view that is. Whether markets work or not in achieving a certain set of goals is an empirical matter that can be investigated. I doubt anyone believes that claim to be false.
To argue a priori then is a completely wrong approach to take. We must justify empirically why markets work like they do, not through pure logic. Immediately, though, this means the market anarchist has no a priori justification for rejecting all states. They can only reject the moral legitimacy of every existing state as they are the only states that can be empirically referred to.
Once you reach that conclusion, it is not difficult to see that some anarchists who wish to abolish contemporary existing states cannot justify why all states ought to be justified. In other words, they are anarchists who must contemplate the possibility that some states may in fact be morally legitimate. Thereby, anarchism itself cannot be a philosophy that stipulates that the state is intrinsically morally unjust.
This view of anarchism is called a posteriori anarchism. Unlike the term a priori, a posteriori means to come from experience. This form of anarchism is a form of anarchism because it believes that currently existing states are in fact morally unjust. Morally unjust states ought not to exist. A stateless society would in fact be better than having these morally unjust states in existence. This form of anarchism does advocate a stateless society as well.
Unlike a priori anarchism, a posteriori anarchism cannot denounce the morally legitimacy of all possible states. So even though a stateless society is advocated by the anarchist, there is room manoeuvre for them to support morally legitimate states. Any anarchist that find the concept of anarchism supporting morally justifiable states as contradictory to anarchism are in fact confusing anarchism with a priori anarchism.
The argument in favour of a market anarchy is one example of an a posteriori argument for anarchism. Another is that all existing states oppress individuals freedoms which is a function of the state as we observe them that makes them morally illegitimate. Unlike Wolff’s argument, the only abstraction here is one derived from our empirical experiences of how states behave and how they are designed to exercise their functions.
Due to this, the a posteriori anarchists can’t preclude the possibility that a state designed in a certain way may in fact be just. This anarchist can support a stateless societies because no arguments have been put forward that argue that some states are morally unjustifiable. Note that this is different from saying we have an argument that all states are morally unjustifiable, the absence of a positive argument in favour of a morally legitimate state isn’t proof that no such argument exists.
It is this reason why a distinction is needed between these two formulations of anarchism. Both advocate stateless societies, thereby qualifying themselves as being anarchist philosophies. One argues in favour of the position that an intrinsic property of the state that makes it morally illegitimate, while the other refers to how states in the world around us have functioned and behaved in morally unjust ways and therefore should be abolished in favour of just ways of organising societies. Confusing the two is to disservice the rich body of thought that anarchism provides.