Suppose there are different ways of knowing and/or believing something. Say, one way to believe something is to become intellectually convinced of it through reasoned argument, but another way to believe something is to experience it.
The difference between believing the tree in my back yard is real because I told you it is, and one night stumbling into it.
So, can you choose to believe?
Most people cannot actually react to a reasoned argument unless the opinion comes from someone they trust. The factual content is nearly irrelevant, in fact, most people will adopt ludicrous ideas so long as they think fondly enough of the speaker of them.
Experiential assimilation has its flaws as well, in that it depends on your subjective impressions shaping the information. Effectively what you learn must adhere to your framework of knowledge and likewise you will reject that information doesn't sit well in this hierarchy. (You simply trust the accumulated body of information more than the new information.) The receptivity to the information is strictly governed by whatever you decide is acceptable at that moment. Without some critical failure in your usage you're likely to plod on right as rain. If the failure was not perceivable to you it's unlikely you will change at all.
These weaknesses are rather hard to address, but the place to start is realizing both you and the person you speak with are correct in different ways. Rarely does any particular choice have no merits despite how abhorrent you may feel it is. It's better to sell ideas and buy them in the context that you both gain through awareness of the options. The lack of awareness is the ultimate problem - realize when to quote the "authority" and when that authority is venturing into the fringe. Be more aware that your opinions are shaped by your environment and your ability to currently perceive them. Stop letting your mind play card tricks with itself and maintain adaptability toward the reception of ideas knowing that any time what you know could be out window tomorrow. Stop identifying with the ideas with your personality as well. Ego really messes with both things as well - your authority can be wrong, you can be wrong, and even the person you argue with can be at ANY time. And, that's OK.