To be more specific, I would like to address what I mean by "Free Thought". Basically I believe that "Free Thought" is my right (if not obligation) to skeptically evaluate the facts available to me in order to form my own opinion on any subject at hand.
This pattern of thought may be used to evaluate statements or opinions offered by others or it may be used to derive my own hypotheses. Evidence to support any opinion is a requirement for my consideration.
I try to apply this to just about every aspect of my life. Misinformation has always been amply available over history and has been reaching peak availability in recent years with the many forms of communication available. There is still a lot of good, valid information available but the "signal to noise ratio" from the vast supply of misinformation makes forming rational conclusions an increasing challenge.
I am a scientist by training and inclination. Even though I have spent more than 40 years working in Information Technology, this scientific approach has served me well whether solving technical problems, picking technical solutions from vendors or working with people and organizational processes.
I take nothing "on faith"! I find most people that say "trust me" are typically unworthy of trust. Being a scientist, while I seek "truth", I know I will not find it. I will, however, find the best approximation to it based on the knowledge at hand.
I find it to be a good practice to chronically "debunk" much of what I hear. This is typically a process I keep to myself lest I annoy those around me though sometimes it is hard to hold my council. Good subjects for this exercise are advertisements and utterances of politicians.
I cannot understand folks that will take anecdotal evidence on just about any rubbish (e.g. homeopathic medicines - an oxymoron if there ever was one) but will reject out of hand scientific evidence (e.g. the safety and efficacy of childhood vaccinations).
I can't believe the ignorance of someone who claims something scientific can be ignored because "it is just a theory". An accepted theory is about as high as it gets in science. It comes after gathering "facts" (agreed observations), formulating a hypothesis on the relationship between the observations, testing such a hypothesis for consistency and predictability, undergoing peer review and having others attempt to duplicate the results of any experiments and finally getting the odd surviving hypothesis accepted as a "theory".
A theory will still be challenged as more and better facts become available or as test and measurement methods improve. Often these add enhancements to the basic theory. A classic example is Newtonian Mechanics. While the more advanced theories of relativity and quantum mechanics have addressed special conditions at extremes of size and speed, the same basics developed by Newton were more than adequate to plan man's trajectory to the moon and many other space exploits.
It does not matter the subject. Any conclusion needs to arise from critical thought. We need to make our decisions based on the best information available at the point in time. Just because someone has written something in a publication does not make it unworthy of challenge.
I choose to make my life decisions based on rational, open-minded thinking and I further reserve the right to change my mind as better information becomes available. That is "Free Thought" to me.