Principles of scientific rational thinking:
No idea is true just because some authority says it is true. That includes you, and includes me.
Think for Yourself and Question Yourself
Don't believe something just because you want it to be true. Belief alone is not a criterion for truth.
Test ideas by evidence from observation and experiments
If a favorite idea fails a well designed test, it is not true. Get over it.
Follow the evidence wherever it leads
If something is proven wrong, then just accept that it is wrong.
And, if you have no evidence, just reserve judgement. You don't have to take a position for or against an idea.
You could be wrong
We are humans, and we may not have all the facts, so we are sometimes wrong. Accept that, and move to more observation and experimentation.
The above is adapted from Neil DeGrasse Tyson's Cosmos: A Space Time Odyssey, episode 13.