The concept of extremism is typically treated as a relative quality based on placement on a one-dimensional scale. For instance, if most of society adheres to position x with "mainstream" differences occurring to a distance y on either side of it, then a position exceeding y in distance from that average value is traditionally considered extremist. This model is not useful, and pursuit of standards based on it yields mediocrity and Overton Window-dependent centrism rather than a productive evolution of ideas.
In reality, extremism as a phenomenon has very specific distinguishing characteristics that are independent of relative position, and this leads to the model I would propose: Meme autoimmunity. As I discuss below, this model is useful in allowing us to identify ideas as extremist based on their intrinsic structure rather than relative characteristics that are too easily manipulated to be meaningful.
Importance
Why is it important to properly identify extremist ideas? Most people's social consciousness is relative rather than objective, and thus societies are inclined not to give full consideration to ideas perceived as extreme under the conventional model. If the intelligentsia and politically active members of society accept that model, what results is (at best) stagnation and lack of creativity in addressing problems. If, however, these social sectors reject the conventional model without having a better standard to replace it, the result is impotence in the face of unchecked meme proliferation.
It is not practical to give full rational consideration to all ideas, especially in the age of the Internet with ever-increasing rates of meme mutation. Rather, people need a standard by which to quickly recognize ideas that have no intrinsic merit, allowing them to be reliably dismissed at minimal danger of ignoring potentially important perspectives. Common sense, while an important tool in everyday life, is itself too often subject to unstated assumptions that become dangerous in a rapidly evolving political environment.
Meaning and Fundamental Definition of Extremism
I offer the following definitions:
Irrational: Illogical or unempirical thinking.
Centrism: An irrational political instinct to prefer ideas at the relative center of the Overton Window.
Dogmatic: A subset of irrational ideas promoted in the face of proof to the contrary.
Extremism: An irrational, dogmatic viewpoint that attributes infinite positive or negative value to an idea.
I further offer the following diagram to illustrate these definitions:
Conventional Model
This definition is extremely useful (no pun intended), but recognizing that a given idea applies is not necessarily straightforward. For instance, suppose that one hears the following statement: "Top marginal income tax rates should be 40% on the federal level." If one accepts the conventional view of extremism, then one's willingness to entertain this proposal will depend on current tax rates.
In a tax environment where the rate is presently 5%, orthodoxy would hold the proposal to be radically progressive, but in an environment where the rate is 85%, the proposal would be held to be radically conservative. In other words, the conventional model of extremism is revealed to bear no useful indication of the value of an idea, but rather to be a self-justifying tautology: One is declaring an idea to be not worth considering because it isn't already accepted.
We also see that the conventional model judges ideas based on their most superficial details without looking at the underlying structure. The proposal noted above, and the person making it, would be labeled extremist under a wide variety of conditions without any indication of the process that led to it. Under those conditions, an idea that is of the utmost rationality and practicality would be summarily dismissed, while under other conditions it would be entertained as a serious proposal even if it had no rational basis.
Application of Definition
"Why?" This is a very simple question to ask, and yet one that is surprisingly rare in politics. The answer to it forms the basis of a simple, practical test for extremism. If we ask that question of the tax proposal above, there are only two types of possible answer: Ones that address the specific rate, and ones that address the relative rate. A justification based on the specific rate would explain why taxes should be at that rate, whereas a relative-rate answer would focus on justifying the concept of moving the tax rate in a given direction.
An argument based on the specific rate doesn't care whether 40% is a tax increase or a tax cut, it's just where the rate should be. But to a relative-rate perspective, the only important point is the direction of change - i.e., whether the proposal cuts or increases taxes. Thus a relative-rate argument would be advancing the notion that it doesn't matter at what rate taxes are, but only a process of change whose limit is an absolute maximum or minimum.
Because such an argument does not make a specific case for the absolute maximum or minimum, but only for pursuing the limit as far as it will go, we see that it places either infinite or infinitely negative value on federal income taxation. Thus it fits the definition of extremism, even if the objectively optimal tax rate were 39.9% or 40.1%. In fact, it would fit even if 40% were optimal, because it makes no argument for 40% itself - it just says raise/cut taxes, and 40% is merely a temporary rate advocated on a tactical basis.
Meme Autoimmunity
We are led inexorably to an even broader and more general understanding of extremism: By applying infinite value to a concept, the result will inevitably be to apply negatively infinite value to its opposite, which gives rise to the phenomenon of eliminationism - the desire, if not behavioral tendency, to seek the complete annihilation of an idea from society, sometimes to the point of attempting to exterminate groups of people associated with it.
Historians have often debated how such originally humane movements as the French Revolution and socialism could have spiraled into murderous nightmares like the Reign of Terror and Bolshevism. In the case of revolutionary France, what made its descent into hell all the more puzzling was the very different experience of the American Revolution: A movement that, despite being led by similar classes of people, involving the same rhetoric, and being inspired by the same Enlightenment ideals, resulted in a more or less functioning, free republic while France ended up creating the model for modern totalitarianism.
The key difference was in the fact that the British monarchy was already constitutionally limited, while the French monarchy was absolute and woven into the very fabric of French society for centuries. Americans were therefore prone to see freedom as the natural expansion of a democratic culture already substantially present in Britain and its progeny, while the French - despite having a deep intellectual appreciation for the abstractions of freedom - were increasingly drawn into conceiving of its reality only in terms of the elimination of existing institutions.
The executions of the royal families in both the French and Russian revolutions were rationalized on the grounds of preventing the restoration of monarchy, as its elimination superseded the humane ideals the movements behind them rhetorically alluded to. They were not trying to guarantee freedom, but simply to exterminate monarchism and all institutions associated with it (e.g., the church), and to the extent this violated the Enlightenment principles that precipitated revolution, those principles were soon regarded as the enemy.
Over time, their determination to remove all traces of The Enemy from society led to an ever-widening circle of disposable "suspects," until every single aspect of people's lives was scrutinized for the slightest hint of "counter-revolutionary" tendencies. Failing to clap loudly enough, long enough was grounds for suspicion, and suspicion was death, so now people who had claimed to be motivated by pursuit of freedom had created a totalitarian society. So determined were they to remove the threat, they became the threat.
Enter the concept of autoimmunity. Organisms defend themselves from disease with an immune system that recognizes and destroys alien pathogens, and sometimes that includes destroying internal tissues that have become dysfunctional or gone rogue. Unfortunately, the cells that do the destroying are not very discriminating, and if they come to identify as pathogenic something that looks very close to a healthy cell, they may wind up attacking healthy cells along with the pathogens. This is called autoimmunity, and extreme manifestations occur in disorders like lupus, where the body's own immune system can destroy internal organs and cause death.
In other words, a system that evolved to stop attacks on the organism ends up conducting them itself; a system that evolved to keep the organism alive ends up killing it. This is the exact same ironic dysfunction as the historical cases outlined above, so we can now draw an analogy that extremism is a form of meme autoimmunity.
In late ancien regime France, the monarchy was dysfunctional and causing its people to suffer. Out of this suffering arose a revolution that ended the direct cause of the suffering, the monarchy, but the revolutionary state did not then turn its attention to building up democratic institutions: Rather, it began to pursue and destroy people associated with monarchy, then people with ideas that looked like monarchy, then people whose ideas were insufficiently anti-monarchy, and finally everyone was suspect - everyone was under attack, and the slightest false move or careless word triggered execution. It was an autoimmune response, and it destroyed the first attempts at French democracy in their infancy.
Likewise, modern capitalism has had periods of unchecked power and wealth accumulation (such as this one) attended by generalized suffering and political corruption, and what has usually followed are reform movements that sought to protect workers and consumers, and improve living standards for the majority of people. One of those movements, beginning in the late 19th century, was socialism - a humanistic, progressive movement that was overwhelmingly democratic in character, and sought to encourage equitable distributions of both power and wealth. Many socialist movements were quite successful, at least in forcing mainstream political groups and leaders to adopt some of their specific proposals. This was a healthy immune response to the pathogen of cancerous exploitation.
But, unfortunately, some socialist movements ceased to fight for worker rights, and instead focused on eliminating capitalists. They lost interest in making life better for average people, and instead focused on trying to purge the underlying psychological impulses behind profit-seeking from society. As with the French Revolution, the list of disposable people just kept increasing - first royals and wealthy industrialists, then aristocrats and merchant bourgeoisie, then "kulak" peasants who had slightly more property than their neighbors, and finally, just as before, anyone who just didn't seem enthusiastic enough about the whole thing. Millions of people starved to death under revolutionary governments born out of cries for the end of poverty. It was yet another example of an autoimmune response.
In the United States in the 1970s, the federal government slightly overreached by instituting price controls on a number of commodities, causing sudden changes in resource availability to be translated into shortages. There was also too much spent on direct welfare assistance and too little spent creating jobs through infrastructure development, resulting in substantial inflation. These conditions hardly qualified as "suffering" in the sense that the French and Russian victims of monarchy, or the slave laborers of 19th-century capitalism knew it. Yet, nonetheless, dissatisfaction and anxiety were the rule.
A healthy immune response to these conditions would have been a modest retrenchment of regulation and a significant shift in spending priorities toward infrastructure over direct assistance, but unfortunately Ronald Reagan was waiting in the wings to take over the White House, and began our nation's headlong plunge into anti-tax, anti-regulation, anti-government extremism. The first things on the chopping block were social programs and industry regulations, but the list soon expanded to education, healthcare, research, and basic economic infrastructure.
By the middle of the Bush/Cheney co-dictatorship, prisons and even many military functions had been privatized, with an essentially non-functional federal government run by people whose sole objective, apart from guaranteeing their own power, was to maximize private sector money and power. The basic foundations of the economy had been eviscerated, along with most of the protections instituted since the 1930s, and year after year of top-level tax cuts had flooded the stock market with speculation.
When the mother of all bubbles burst and created the mortgage crisis, the United States had no choice but to spend trillions to bail out banks, even as unemployment skyrocketed and the threat of inflation loomed. And thus, the modern conservative movement born in dissatisfaction with relatively modest economic problems became the agent of the greatest economic disaster since the Great Depression, having destroyed the very economy it purported to enable and protect.
Today, we are stuck dealing with the degenerate remnants (revenants?) of Reaganist extremism, who have doubled- and quadrupled-down on their infinite valuation of the private sector, and infinitely negative view of government. And while the situation on the left hasn't gotten anywhere near that bad, there are weak indicators of new strains of anti-capitalism primarily concerned with destroying rather than sustainably regulating business. The anti-government elements are of far more concern at present, but it is wise to be wary of extremism - as defined in this diary - in all its forms.
Remedies
It should be noted that the opposite of extremism is not centrism. In fact, due to centrism's dependency on the Overton Window, it can often enable extremism by lending its weight to irrational or immoral ideas that have become the "middle" of the newly-framed window. While I would like to arbitrarily say that "liberalism" is the opposite of extremism, there is no generally understood term that communicates the concept in a more elegant way than the klugy "reality-based thinking."
Aside from the definition already articulated, and the examples given of infinite-valued thinking, a handy heuristic for identifying extremism is its emphasis on elimination and ideological purity. Healthy, reality-based political viewpoints seek to solve problems not by elimination, but by arranging systems to automatically and organically balance against them.
We do not seek the eradication of irrational or immoral ideas, and certainly not the people associated with them, but rather to have a society and political system where reason and morality are naturally stronger influences than their opposites. We seek a society with a healthy memetic immune system that can simply tune out useless or dysfunctional thinking, and does not empower extremists whose motivation is to eradicate people and ideas they deem threatening. At our best, we at Daily Kos are that immune system. Let's try to keep in mind the level of responsibility that entails, and not become what we behold.