Politics have a fundamental dichotomy that centers on the split between progression and conservation. We cannot agree amongst us wether we should evolve or preserve. I believe that it is self-evident that no species can preserve itself if it does not evolve. Nor can it for equally self-evident reasons, evolve without preserving. However, rightful trepidation about that which we don't know and confidence with that which we do know and have mastered tempts us to be conservative. But curiosity and hope for a better condition continuously agitates us to be more progressive. On a social, at times even personal scale, we have a hard time reconciling the two.
The split between so-called conservatives and so-called liberals does not neatly fit into the dichotomy progression/conservation. This can be evidenced by the repeated use in the last two decades of the term "neo" which is used for those that defy a neat classification ("neo-conservative" versus "neo-liberal"). Sometimes those deemed liberals are in fact struggling for preservation (especially within the context of the "environment") and sometimes those deemed conservatives are fighting for progression (such as globally spreading democratic values through the use of military and economic power).
Importantly, any time a group advocates in the abstract for social change, there is almost always a reciprocal force advocating for preservation. Until some drastic event with widespread repercussions forces nearly everyone to realize that the current conditions are untenable. There is a sudden moment of instability where uncertainty approaches its maximal 50/50 position. Conservation is no longer an option. Even to restore a pre-existing condition, we must now go through a period of active change (as opposed to "maintenance").
In the short term, there is another option: doing nothing ("laissez faire"). But this option only remains viable if signs of a tolerable stability are quick to appear. Of course, what is tolerable is sometimes a subjective matter. But the availability of decent food and shelter is an objective and commonly shared measurement. More importantly, the state that existed prior to the phase of instability can be used a baseline for what is acceptable to most. The strategy of doing nothing and await less turbulence quickly wears thin.
It could be claimed that trying to restore what once was is not progression. Progression is to some extent subjective. Whether we are progressing depends on the what we have set out to achieve. But in a state of near maximal uncertainty, restoration can be considered a widely acceptable short-term measure for progress. When we have temporarily restored stability, both sides along the political spectrum begin to brainstorm what changes are required to either conserve or improve our future condition. Society opens itself up to transformation on all fronts. This is when the progressive agenda has its greatest potential to alter what is considered a desirable state of affairs (to set new measures). This opportunity is short-lived since the longer we have stability, the less prone people are to risk change. Conservative agendas have most traction in times of stability.
I see two main reasons for sudden social turbulence: natural disasters and technological advances. The former disrupts by removing existing opportunities whereas the later disrupts by creating new opportunities. Any stable society is replete with opportunities for most: the opportunity to work, the opportunity to eat well and afford good shelter, the opportunity to learn, and so on. A natural disaster eliminates these possibilities by destroying the infrastructure by which we realize our potentials. Technological advances, on the other hand, create new ways of exponentiating both our potentials and the speed by which we can fulfill them. However, the consequences of these hitherto unknown potentials and the rapidity with which we can achieve them, are not predicable. Any major technological advance always initiates a period of social experimentation.
As well understood and practiced ways of going things are replaced with novel approaches, a turbulent trial-and-error period is almost inevitable. I myself experienced this during the late 90's as an emerging architect of Internet-based software. We had social visions but only marginally understood the new systems at our disposition. And the systems kept changing based on our newly acquired experiences with deploying these systems in real contexts. We could only loosely predict side-effects of any proposed designs since we lacked any factual data. It's not just that excessive exuberance lead to a financial bubble. We are still today dealing with how to remedy problems that Internet technologies have introduced: spam, Nigerian scams, phising, copyright issues, the ease with which people can encroach on our privacy, only to mention a few.
The reasons that I mention for sudden social turbulence don't include cultural and ethnic aggression. I think such aggression is a consequence of removing or creating new potentials, not a random act of bigotry or a sense of moral agency. Most people just want to live a comfortable life in the context of there immediate social sphere. The Alexanders and Hitlers of the the world are an aberration. Warmongering by leaders becomes possible when natural disasters destroy potentials or technology creates new potentials. War then results in further human induced destruction and possibly mass exodus, which further destabilizes and perpetuates aggression. Sometimes a self-sustaining vortex of suffering results. But the root causes of such turbulence remains natural disasters and technological advances.
The solution to control turbulence caused by natural disasters is technology. If we can predict a volcanic explosion, we can avoid untold deaths. And if we have the means to quickly move old and build new infrastructures, those displaced by an event like Krakatau can quickly return to normalcy. As another clear example, famine has been largely (but not entirely) controlled in the world through more disease resistant crops, better transportation and improved irrigation techniques and fertilization. However, the fight against famine illustrates the problem with technology and its unforeseen consequences. An excessive amount of synthetically produced nitrogen fertilizer now threaten the biodiversity of our oceans by causing toxic algal blooms and thereby negatively impacting our fishing industries.
So technology is both the antidote to and cause of social upheaval. The question then is how do we eliminate the turbulence caused by technological advances? We can't just become ultra conservative and stop the progress of science and engineering (note that I include in these fields the science and engineering of the social organisms that make up human society). To some extent we have to accept that a certain degree of risk is involved in any evolutionary process. But excessive risk, given our increasing ability to affect our environment, could spell the end of humanity and its descendants as such.