@Briancrc,
If free will is a metaphysical idea, then it can't be proven OR DISPROVEN with ANY evidence. Metaphysics, by definition, are beyond the realm of empirical evidence ("physics"). Determinism for instance can't really be proven or disproved completly with experimental evidence. Hence it is a metaphysical assumption. A subject for pure philosophy. In other words, it's irrelevant, just as gods are.
I believe free will is a practical issue, or at least that they are practical, empirical aspects in some views of free will. So it's not purely metaphysical and we can thus conduct scientific experiments about it. In short, unlike determinism, free will is falsifiable.