‘Changing his free will’ simply means changing one decision for another. You have a reason for the original decision and then something happens to cause you to choose another option. And there would be a reason for that.
And self reflection has to relate to the external world. You are contemplating how you interact with the world. Maybe you should be more humble. More forthright. More caring. More thoughtful. Everything that you internalise has a connection with the external world. And what happens in the external world gives you reasons to ‘self reflect’. People’s reaction to you, either directly or indirectly.
Your fat guy had a reason for being overweight. And then something happened to cause him to change his mind. There was a reason for that as well. Maybe medical advicd. Maybe he couldn’t tie his shoe laces. But there is always a reason for all the choices we make. And if you had exactly the same conditions then you would have exactly the same reasons for making exactly the same decision.
As I have said on a couple of occasions, if you made a choice not governed by reason then you’d be a useless member of any jury. What you are suggesting is that you could hear all the evidence in a case presented in exactly the same way under exactly the same conditions and come to a different decision.
How do you explain that?
One would hope that a change of attitude or disposition has a
reason but that change can also be rooted in
emotion.
The point is that externalities cannot, in themselves, change attitudes, i.e., our internal dispositions. We are not simply blown about by the wind, responding to the laws of nature, or driven by unchanging instincts. If we did not have a reason to change, we may be called whimsical. But that does not alter the fact that absent free will, even the whimsical could not change attitudes.
The
direct cause of any change in disposition is internal. Anyone not living in a vacuum may have
indirect external causes but indirect external causes are neither necessary and, most certainly, insufficient to effect an internal change. Only a free will can explain one’s ability to change an attitude.
Your characterization of self-reflection as always relating to the external world misses the point. We are not blackboards upon which others write our story. We
internalize all our experiences through self-reflection, i.e., the act of
freely deciding what to keep, what to ignore as our own. If you read this post, you’ll do just that, self-reflect and freely decide. If you didn’t have a free will, well, you’d be following the advice of the last person you listened to.
Your jury example merely re-expresses your same false argument that because
what has been will always be, so therefore, we do not have free will. It’s a
non sequitur fallacy. The argument says nothing about the state of free will in the moment in history, only that one cannot change history.