We all have opinions — this is a good thing.
But, we also need to know our limits. Sometimes our opinions are worthless because there are clear objective facts. Sometimes, new evidence surfaces that require us to change our opinions.
Being flexible in what you believe is not a sign of a weak mind or a fickle personality. It is a sign of a clear understanding that reality is above all opinion.
A great question to ask yourself about your own opinions is this:
What evidence do you need to see that would convince you to change your mind?
Or, in other words:
What would need to be true to change your opinion?
If you can’t think of anything, then you do not hold an informed opinion — you hold a dogmatic position.