How would thinking be determined by exterior stimulus, when we all vary to some extent to the same stimulus? Behaviorism was found wanting because it didn't account properly for goes on between the ears. And the rest of the body, which makes us individuals. The idea of free will comes from the fact that people do make different choices. We make different choices than our past selves did. From a compatibilist perspective, one could say free will comes from being part of determining what goes on. Things don't just happen to us. We participate in what does happen. We're not simply puppets on the string of the external world. We're just as much a part of causing things as everything else is.
> How would thinking be determined by exterior stimulus, when we all vary to some extent to the same stimulus?
Because, and this may shock you: we are not all the same person
You make an excellent point that people respond differently to a given stimulus. This is explained by those people having had different genetics, environments, upbringings and even breakfasts leading up to the point of the test. It has been demonstrated that your metabolic state will vastly change your response to stimuli throughout a day.
I ate something different for breakfast today than yesterday because one sounded tastier than the other. I made this decision not because I have an eternal soul making randomized decisions like a roulette machine but because yesterday I craved salty food and today yogurt sounded better. I am different person today than I was yesterday. My gut, brain and everything else has been changed by all the stimulus I experienced yesterday and is now influencing my responses today.
