I want to understand the circumstances and/or examples of subject matter for which you can not learn to understand them without putting aside skepticism.

I get that if a person has a big complicated set of ideas that contradict a new set of ideas, they may need to set aside the old one while they build the basis for the new one. But is this technically necessary?

How would you do it if they have a fear of being (figuratively)“brainwashed” by being asked, as a condition of exploring the new set of ideas, to begin by supposing some of its base assumptions are true – assumptions they think are false but are open to reconsidering?

Being told I may need to be clearer.

Try 2:

I want to learn about some ideas I think are probably not true. If I am told to try thinking of them as true in order to witness that they are true, what should I do?
Are there subjects for which that could be a necessary requirement?

This isn’t the subject but as an example:

What if someone said that in order to witness that God exists, you must first try believing that God exists?