Proof is a pretty strong requirement. A lot of things happen for which we never find proof of cause. A house catches fire or an animal dies. Why? We may never know. We may have a very good idea, but lack the necessary proof to make an unequivocal determination; however, this doesn't mean we can say neither was caused. On the other hand, there are a lot events for which we do have proof. It all depends on the event and the evidence. In any case, events, including decisions, are either caused or they are absolutely and utterly random, just flashing into existence out of nowhere. Neither leaves room for free will. As it stands, the only known truly random events take place at the quantum level. ALL others are determined by prior factors. No freedom involved.