Free thinking means thinking without deferring to authority.
It means using that organ between your ears by yourself – arriving at your own conclusions about the universe, without influence from nation, race, language group, tribe, philosophical school or political party.
We learn from others, yes. But when it comes to the truth, our own minds must be the final court of appeal.
Therefore, free thinking is thinking. It is one and the same. When you are thinking you are doing the opposite of surrendering your mind to authority.
You are using the organ the way it was meant to be used.