I tried to change my brother's beliefs. He gets motivated by some bad ideas. Following my attempt to change his beliefs, his beliefs have become even stronger.
It's a little unclear to me from what you've said that your efforts are truly affecting your brother's ideas. It's also unclear whether those ideas are objectively bad, or whether you should be trying to change them. In general, we have to be careful to avoid recommending specific actions for specific people here.
That being said, the general phenomenon you seem to describe is reactance. Excerpts from Wikipedia:
You may want to follow some of the hyperlinks above. They're all useful concepts for this issue, and may help you understand what you're doing and what your alternatives are. As a general principle, counselors and therapists avoid trying to change others' beliefs and attitudes explicitly and directly. Instead, they focus on understanding their clients, and in the process, they prompt their clients to reexamine themselves and find their own reasons to change. It's subtle yet impressive social jujutsu.
- Brehm, J. W. (1966). A theory of psychological reactance. Academic Press.
I would like to put an answer based on my experience in training and coaching others. I used to shoot small video conversations (up to 5 min) and than we analyzed carefully. Analysis took up to 30-40 min. By doing this we could see every small emotional changes during argumentation/communication process.
After 2 years of such experience I can say that the most common mistakes are:
Competitive position provokes competition in 50% of cases. So if one wants to influence important to be open to others position. It is hard but really helps to establish partnership and trust.
It increases stress. It is better to find things to which you both can agree. There are always some points but usually we forget about them especially under high emotions.
By this you can forget about the person in front of you, about his/her emotional state which is more important than any rational arguments. He or she may be angry at you and hardly listen. To avoid this important to react at your opponents reactions. See him/her nodding or having sceptical grimace? Ask, talk about it.
Otherwise its only in your own head you are a winner with the best arguments ;)
Its important to clarify all the details: opponents positions, logics etc.
Any type of dominating can provoke negative emotions.
When you start your communication with strong assumptions that someone beliefs are bad and wrong one can feel it and start to protect it.
Partnership, openness, trust, respect, clarity helps to persuade others. The key is attention to emotions of your partner, we are not so rational as we wish to look like. When you really want to understand him/her position it feels and that is where your dialog can start. It sounds simple and even as some basic stuff but it works both in persuading and in establishing good relationship.
For the most part, you don't change people's beliefs. When deeply held beliefs change, it is often due to a change in self image and often triggers further change in self image.
So, asking someone to change deeply held beliefs is tantamount to asking them to change who they are. I agree with the previous replies that you should really question your desire to change someone at that level.
If you want to change other's people beliefs you will have to work hard on yourself before. Start by reading this page from Wikipedia: How to Win Friends and Influence People.
PS: the one who wrote the book was also the mentor of Warren Buffet. This guy has become millionaire.