We like to think we are logical and have good reasons for for our beliefs. No more so than when it comes to our reasons for rejecting the truth claims of JWs.
We reject their version of history, such as the date of the fall of Jerusalem, because it doesn't agree with the historical evidence. We reject their claim that we are living in the time of the end because there are not more wars, famines, diseases or earthquakes now that at other times in history. We reject their interpretation of the "generation" of Matthew 24 because it doesn't make sense contextually, linguistically, or logically. We reject their version of creationism because the evidence shows that life evolved slowly by natural selection.
But it seems to me that while these are some of the reasons we might give for rejecting JW beliefs, what actually persuades us to reject those beliefs in the first place is often quite different.
One of the most important aspects of persuasion is social proof. We see other people leaving JWs and this persuades us that there are good reasons for leaving JWs. In logical terms this is a fallacy known as the bandwagon argument or argumentum ad populum. In this sense, it is the very existence of this site, its popularity, and the number of stories of leaving JWs it contains, which gives it persuasive power in drawing people away from JWs. Not the detailed doctrinal or historical arguments, but the stories of leaving, their volume and relatability.
Another important fallacy involved in persuasion is the genetic fallacy. Maybe others have had a similar experience of studying something for a long time to try to work out if it is true. You make arguments in your head for and against and go round in circles. This can go on a long time, but it's when you realise the history behind a particular JW truth claim that a lightbulb goes on and you realise it just cannot be true. Take 1914 for example and now you can get bogged down in translation issues, astronomical data, ancient cuneiform. You can get incredibly detailed if you want to spend days and weeks researching this. On the other hands just a few key peculiarities of the history of the doctrine can psychologically undermine it much more than empirical data. For example the fact the size of the pyramid was used to support 1914, that the date was changed from 606 BC to 607 BC to make it fit, that Russell got the date from other Adventists, that president Knorr said he didn't necessarily believe it, that they say Satan was kicked out of heaven in September/October but World War 1 started in August already... this could be a long list.
So often it's the historical circumstances of a teaching that undermines it more than logical arguments for and against. Refusing blood transfusion arose when donating blood was patriotic during wartime and vaccines were also stigmatised. Disfellowshipping started around the time Olin Moyle was kicked out of the religion and hardened following Raymond Franz's departure. Psychologically these details seem to harm belief in these doctrines more than a deep consideration of scriptures or arguments or logic.
Another thing that often persuades us JWs are wrong is the sheer weight of expert opinion that JWs are wrong about key issues. People are hard wired to respect authority and expert opinion. JWs do an excellent job of neutralising this in their literature by 1) arguing that not all experts reject their views such as about evolution and 2) providing their own experts to support their claims. When we were naive JWs we often assumed that experts were simply not in possession of all the facts. If they read the Creation book or considered things dipassionately they'd realise they are wrong to believe evolution. However if we expose ourselves to books that explain evolution clearly we realise that experts are well aware of the type of arguments JWs make and they do not find them compelling. We also find out that experts JWs claim are on their side are either being misrepresented or their credentials are not what they are cracked up to be. So we reject JW beliefs because they are supported by dubious means. We didn't realise how much expert opinion weighs against JWs because we were discouraged from reading such matters or studying them. So when we realise experts reject JW claims directly and unitedly this does a huge amount to undermine belief in JW teachings.
From personal experience I have noticed that arguing with a JW never convinces them they are wrong. If you want to convince a JW you need to persuade them not refute them. This requires a very illogical approach as explained above.
Having said that, while persuasion might be more effective than refutation, it is still not very effective. JWs will often only be convinced JWs are wrong when such a conclusion aligns with their own interests.
Logical arguments only work with people are are already convinced. Amd persuasion only works with people who want to be persuaded.
Displacement may be more effective than either persuasion or refutation. In other words, instead of arguing JWs are wrong, or undermining JWs by appealing to authority, the genetic fallacy or bandwagon effect, don't say anything about JWs at all. Ignore the subject and suggest doing something alternative instead of the ministry. Then instead of the meeting. Then make it regular. Maybe the best way to win an argument with JWs is to avoid the argument.
Just some ideas. What do you think?