In disputes upon moral or scientific points, ever let your aim be to come at truth, not to conquer your opponent. So you never shall be at a loss in losing the argument, and gaining a new discovery.
Arthur Martine (As quoted by Maria Popova of Brain Pickings)
It is incredibly difficult to change minds. Even the strongest arguments, with the best supporting evidence, will seldom cause any kind of crack, let alone foundational mind-shift. Opinions and world views tend to set over time, and they become more resistant to being chiseled away at.
The reason our minds become so solidly set mostly has to do with cognitive biases like confirmation bias, loss aversion, the bandwagon effect and the just-world phenomenon. I don't want to go into these in great detail here, as fascinating as they are, so in short: cognitive biases essentially work because we treat ideas and information like we do physical possessions. That is, once we 'own' them, we protect them, assign them a higher value than they would ordinarily have, and, of course, we see them as markers of our social, cultural and economic place in the world.
The problem is this: that many of our treasured ideas are quite simply wrong. And even though many of us will profess to have an open mind, at the core, we don't leave our minds open for the same reason we don't leave our homes unlocked. Intrusive and invasive external facts which clash with our home ideas are treated with suspicion, and sometimes even actively chased away. It doesn't matter how correct a new fact is, if it threatens our dearly-held beliefs, we are generally unlikely to allow it to steal our old ones away.
The outcome? Put starkly: willful (and often dangerous) ignorance. At its worst, the failure to change minds in the light of better facts and better perspectives results in religious extremism, racism, conservatism, sexism, denialism, homophobia and the view that poverty is a personal choice, rather than a systemic problem. But even in a more mundane incarnation, it results in the acceptance and propagation of all manner of pseudo-science, chicanery and quackism.
So it's difficult to change people's minds. And at the same time, it's essential that people do. And a purely factual argument isn't going to cut it. So how do we change minds?
Here are my ideas:
Shouting and screaming isn't going to change anyone's mind. Try to understand why someone has the perspective they do. You don't have to agree, but you can at least try to understand. Don't ridicule them or lambaste them with facts. Many people believe what they believe because it helps them to make sense of things and to find meaning for themselves. Of course, it is difficult to be tolerant of a bigot or an extremist, and I am not advocating that we need to accept these perspectives. What I am saying is that if you take a belligerent approach when trying to convince these people, they will go into protective mode, and any small chance you may have had to effect even a small shift in their thinking will be lost.
(Also, start with the small stuff. These are the beliefs that are usually only loosely held anyway, and it should be easier for you to try to change these beliefs. You may even find that this is enough, that dislodging a pebble or two triggers an avalanche of self-reflection and questioning. A word of caution though: don't spend all your time trying to crumble away the small stuff, as the person you are trying to persuade may feel that you're eroding everything away from them, and be inclined to put up barriers.)
Make it personal
We all weave our own narratives as we meander through life, and we tend to bend new information and experiences to fit with this narrative. Even though we might know that this is illogical, if we make the effort to try and customize new ideas to at least partially fit a person's private narrative, we will be more likely to effect the acceptance and incorporation of new ideas. Even if it is only partially, or even incorrectly, a small crack provides an opportunity for leveraging a bigger, more fundamental shift.
Minds are seldom changed by sudden epiphanies. More often, a thought-seed is planted, it grows, and slowly, without any sudden observable change, it sends down roots which fracture existing perspectives – or at the very least, dissolves and subtlety changes set ideas into something new. In short: if you really want to change someone's mind, do it slowly and over a protracted period.
Know when to stop trying to persuade someone. It may be best to walk away and return to the topic, especially when a rational argument starts to become emotional. Also, know that when it is becoming more of a clash of egos than a productive discussion, it may be better to stop and to retry later. And yes, there will be times when beliefs are so firmly held, that you simply cannot effect change. As discomforting as this may be, realize that your energies might well be better spent elsewhere. Some minds are just too firmly set.
Find common ground
As difficult as this may be, people are more inclined to make concessions and be more open to persuasion if they feel that they can connect with you on some common ground. In practice, this definitely not always possible, particularly with entrenched bigots, but most often you will be able to find some common ground, no matter how precarious.
Practice what you preach
Be prepared to change your own mind when faced with a better, more logical and / or more factually correct perspective. And show that you allow this new perspective to change what you believe to be true. Be skeptical, but open to considering new, more convincing perspectives. Be open with your inevitable struggles to model what it is like to change your mind, while at the same time showing why and how less solid arguments need to be challenged and refuted. Demonstrate that you are always exploring new ideas and learning new things, as well as challenging the things you thought you knew.
It is so much easier not to challenge outdated beliefs. To be quiet and try to keep the peace. Be courageous and try anyway.