"What is the most dangerous fiction of the last 2500 years?"It depends upon what we mean by dangerous. Dangerous to whom? Fiction derives its power by creating worlds which do not exist, but yet bear enough resemblance to the world which does exist that we are led to draw inferences about reality from the fantasy that can manipulated by what it is intentionally or unintentionally added in and left out.
If it means danger to the power structure, then we can look at works like Uncle Tom's Cabin and The Jungle which take real evil and humanize it by having us sympathize with fictional characters forced to live out in front of our eyes what we are able to successfully avoid by diverting our glances in the real world.
If on the other hand, we mean dangerous to the culture, we can look at a book like The Fountainhead which creates a fictional world designed to further ingrain harmful biases against those who are most in need of empathy. Dangerous fiction is writing that justifies the worst in us by oversimplifying the complexity that we live in.
"Are political arguments (in newpaper columns, on TV, or blogs), as an effort to change people's politics, ultimately futile, if one's political orientation is biological?Multifaceted question. I think that the premise of the question, that some aspect of one's political stance is strongly affected by biological factors is correct. There is no doubt that one's basic stance towards others is a major factor in determining one's politics and this comes at least in part from biology which may be affected by genetic, environmental, or other sources.
"People's values are deeply embedded in their biology and genetic heritage," says UofT Professor and co-author Jordan Peterson. "This means you have to take a deeper view of political values and morality in terms of where these motives are coming from; political preferences do not emerge from a simple rational consideration of the issues."
[ http://esciencenews.com/articles/2010/06/09/personality.predicts.political.preferences ]"
If it were completely deterministic -- if there were conservative or liberal genes -- then the question would be moot. But, of course, it is much more complicated than that. Surely, the Enlightenment picture of humans as rational calculators who weigh arguments and act according to the most reasonable is a gross oversimplification in the other direction, but political discourse does indeed play some active role sometimes in getting some people to change or at least reconsider long held positions.
At the same time, I don't think that opinion pieces are simply meant as rational considerations of issues. They are not meant to persuade in and of themselves. I believe that they are larger aspects of political p.r. No corporation believes that someone watching one commercial or seeing one billboard will suddenly decide to purchase their product, much less be moved to stop buying a competitor's product. But that is not the goal of the commercial speech act. The idea is to create a cloud around the consumer in which the product becomes a normal part of life, becomes comfortable, and thereby an option out of reflex.
In the same way, we have political messaging going on, where the idea is to associate ideas with images or concepts, not create logical inferences about them. This is the genius of Frank Luntz. Don't make arguments to convince people because it doesn't matter whether you are right or wrong, it only matters if you win and emotions are more powerful than logic. The purpose of much political speech to create a comfortable worldview within which one's policy preferences become natural.
This is not to say that we do not want inference within our political views, we do, because we are loathe to admit how much of it is indeed based on emotion and personality and so op/eds and the like often serve to backfill justifications for predetermined beliefs.