Just like anything else, humans have a natural tendency to think that they are right. One of the most difficult things you can do in life is tell a stubborn person that they are wrong. You can present all the evidence, but if there is a belief that they hold true to themselves, good luck.
I have read a couple of negotiation based books in the past because I am currently in a field of work that requires negotiation. It is also helpful for a multitude of life’s scenarios like buying a new car, negotiating a mortgage, or even setting the rules to a game. One of the better books I have read was “Never Split the Difference” by Chris Voss. He was an FBI hostage negotiator and throughout the book he details his methods using real life examples. It is a very interesting read and I highly recommend.
One of the main things I see when people debate is the back and forth of telling the other person that they are wrong. Everyone enjoys saying that if the facts show the answer they will accept them. Problem is very few things in life are black and white. You can easily tell someone that 2 + 2 does not equal 5 by using a calculator, but how can you convince someone that their opinions are wrong?
Perspective is a fickle beast and using politics as an example, the perspectives are completely polarized. You would have to completely shatter a person’s worldview in order to even attempt to break through and implant your perspective. That is almost impossible unless the person is open minded.
One thing the book mentions, and it is usually mentioned in other books, is that if you are going to try to persuade someone, the last thing you want to do is attack their fundamental beliefs. You may be 100% right in your analysis of the situation, but the natural countermeasure to an attack is a defense. It closes off the mind because you pushed too hard, too fast and any chance of getting through is now gone. The mind becomes a wall.
The best way to create a counterargument is to not make any declarative statements at the person who you are engaging with. It helps knowing the facts of your perspective. Instead of telling the person your facts, build questions around your facts to ask the other person.
In short, play dumb.
It sounds stupid, but here is how it works: It keeps the guard of your opponent down because they think that they are the one who is in control of the conversation. You are using that confidence in order to get them to keep their walls down because they are educating you on their perceptions of the facts. It keeps the conversation civil as well.
When you act like you are genuinely curious, your questions that start to shatter their worldview of the subject will go unnoticed. You will start seeing a shift in the goalposts, but in continuation with the constant questions, they will either start to change their opinion to be more towards yours (assuming you are correct) or rage quit.
The reason why this method works as well is because since you are the passive one in the conversation, whatever new revelation they receive, they will think of it as an original thought. This has a deeper lasting impact than them learning that they were wrong by someone else.
Most people, after realizing that they are wrong also go on a studying spree in order to try to figure out if they are wrong on other things as well. Just like when people discovered that most news is fake, they went out on their own to try to figure out what else is fake. This domino effect will have the person do all the work for you as well.
In the pursuit of persuasion, instead of trying to be a hurricane that barges in, be a gentle breeze that guides the person in the right direction and starts a thought contagion.