It's not a matter of predestination of one's beliefs, it is a matter of one's current intellectual ability to understand certain socio-philosophical frameworks, concepts, and ideas, which can only be unveiled by honest self-doubt (such as the fact that what F3lix believes to be his own
free will of choice may actually be an illusion), or by open and honest conversation about how one thinks and behaves, where one's faulty ideas and ways of thinking can be corrected (or validated) by others who have had their own corrected or validated, either by themselves, other people, or some other stimulus.
Nobody is going to sincerely believe that their own free will (particularly if they presently identify as being a Libertarian or Conservative) unless they are more interested in truth (outside of themselves) rather than their own, obviously self-biased opinion. This is called the Great Doubt.
You don't know what you're going to be thinking 10 seconds from now. How much of your mind do "you" control?