Many of the tenets and arguments that are used within cults and destructive organizations would make a scientist spin with the sheer lack of rational logic.
Not only this, but they often outlaw or corrupt real logic to their cause, thereby preventing opposing arguments to be made.
Emotion over logic
In the spectrum of thinking vs. feeling when making decisions, the direction is firmly over to the right, into the feeling zone. Emotion is used in general persuasion, for example where love and happiness are offered as a desirable outcome. Strong anger is used against wrong-doers and fear is used as a common persuasive tool.
Passion persuades. When a person seems to feel strongly about something, we feel a sense of empathy as our natural systems pick up and copy their feelings. In this way, an emotional argument of any kind is often more persuasive than cold logic.
Logical thought and critical thinking may be treated as selfish, attending to one’s own thoughts and ideas in preference to thinking first about the well-being of the group (which is of course an emotional argument).
Assertion over reason
When any argument is being made, the basic principle of presentation is in the assumption that people will agree without challenge. This can be seen in the authoritarian stance that is often taken. With enough apparent conviction, even the shakiest fallacies can be accepted as truth.
When one person strongly asserts something as true, then others who might normally be doubtful may begin to wonder if the person could be right. This is the basic principle of persuasion by passion. While many of us believe reasonable things to be true, we are always open to alternative views and are swayed by the beliefs of others.
When the other person seems not to accept any view but their own, we have the choice of agreeing or falling into conflict. Just to keep the peace, many will agree rather than argue. And once they have agreed, they then have to convince themselves that they are right, and so they may come to really agree with the original assertion (and perhaps become more of an asserter than a reasoner themselves).
Faith over fact
Another way that people are persuaded is that acceptance of the ‘truth’ is made a matter of faith, and that a lack of faith is deemed wrong and bad. The situation is hence reframed from being about whether the argument is true or not, or that the data is correct or not, but whether the listener has sufficient faith.
Faith tends to be an absolute. You believe in the whole canon or you do not. You cannot believe in a part of the teachings. This is how it often dominates and can be used as a hammer to push reason and fact away.
Fallacies as logic
When arguments for any point are being put forward, then rather than rational logic, a perverted rationale is used, with copious use of fallacies to hold up ‘proof’ and ‘truth’. Fallacies can be very simple, such as in the use of basic appeals. They can also be more complex, for example in the use of statistical or even syllogistic fallacies.
The basic principle of fallacy in general argument is of face validity That is, while the fallacy is logically incorrect, it sounds like it is right. This is made stronger with emotion and assertion.