Specifically, Mutualism is a trend of anarchist thought created by Pierre-Joseph Proudhon which is neither explicitly communistic nor individualistic, and which favors absolutely neither gift economies or market economies, which has been revived in recent years by writers such as Kevin Carson and Shawn P Wilbur.
Less specifically, it is the idea that society should be based on mutually beneficial interactions to the highest degree possible, with hierarchical and involuntary interactions minimized.
This is what mutualists advocate for, the simple idea that hierarchy, force, and one-sided interactions are undesirable. According to this principle, most libertarian socialists and anarchists could be considered mutualistic, if only because their beliefs are compatible with mutualism, regardless of whether they specifically identify as mutualists.
It follows from this that things which encourage any of the above are not mutualistic, which is why we reject current property norms which allow for individuals to decide what happens to vast swathes of land and property which they have neither the right nor the need to control, while thousands starve and go homeless, and we reject the state, as it is merely a hierarchy utilized by the wealthy to protect their wealth, no matter what fleeting, temporary reforms like higher taxation or welfare might make you think(which, mind you, all came only after the threat of revolution via the unionized working class, and which still do not grace most countries).
What exactly should take the place of the state, and what form property and the economy should take is still a subject of debate among mutualists and other anarchists, but so long as the organizational bodies that handle things like infrastructure, crime, production, education, etc are non-hierarchical and do not use force to maintain themselves, there is little that most mutualists would find disagreeable.
(Personally, I think the most probable outcome is that society will consist of a mixture of gift economies made up of people banding together to support each other in loosely-knit federations and communities, and organic markets, which is to say markets without the influence of the state or of artificial hierarchy, and that oftentimes the line between gift and market economy may blur or become meaningless altogether)
It should be noted that there is no limit to how big certain organizations might be in an mutualist or anarchist society, and the majority of anarchists not only accept large organizations and collaborations of people, but encourage them. The idea that anarchists support chaos, or that we oppose rules or organization, is largely a myth, which stems from us disagreeing with the current legal system, and from a few anti-organizational tendencies of anarchism which are a minority, and which mutualism is not one of.
Mutualism is not communism, since mutualism is merely a moral baseline and imperative that communism may or may not follow, and we are not abjectly opposed to all forms of currency or markets, since they can both be employed without hierarchy or violence.
And similarly, Mutualism is not “anarcho”capitalism, market anarchism, or right-libertarianism, since capitalist property norms generally result in hierarchy and violence(for example, the way banks and private individuals are able to ‘own’ thousands of houses they don’t use at all, and which they use state force and police to protect), and because we do not believe that “markets” in the traditional sense are any better than voluntary gift economies.
It should also be noted that we are not pacifists, or opposed to the use of force for self defense of oneself, and that there would most certainly be systems in place in a mutualist society to deal with murderers, rapists, polluters, etc although certainly not in the form of the current legal system which is based on centralized hierarchy and which unjustly punishes millions of people for their addictions.
Additionally, there is no reason to think there would be an abundance of drunk driving, speeding, thievery, or other crimes in an anarchist society, since most roads and public spaces would be controlled by the workers and communities who maintain and build them.
Now, you may be thinking “this all sounds great, but how exactly do you plan to achieve this and make society mutualistic?”
As for that, with mutualism simply being a moral baseline, there is no single strategy that we all believe in, but there are a few common ones, and my personal ideas.
When people think of anarchism, they think of revolutions, and of people rising up in revolt against the state.
But, in addition to being implausible in America today, violent revolution is also unnecessary.
Instead, what I put forth is that we should attempt to build non-hierarchical anarchist institutions based on mutual aid in the here and now, and rely on them instead of on the state, or on capitalistic ones.
In this sense, the fight for an anarchist society is not one where we’re doomed to be miserable until the state is abolished, but one where the “level” of anarchism we live in is dependent upon how much we organize, build, and rely on anarchist organizations ourselves.
There are certain things, laws and the de facto dependence on the state for infrastructure such as roads, that we cannot currently escape or take over, only evade and maneuver around. However, this is only a result of mutualistic organization currently being small and relatively insignificant(as in, not currently powerful enough to fight the state for control of many of society’s needs). If in the future mutualistic social relations were to become a significant and powerful force, I have no doubt that the we will be able to fight statist(and capitalist) monopolies.