If your personal philosophy is a form of libertarianism, as mine is, then reliable prediction of brainstates (based on a causal or stochastic model) contradicts the underlying premise. Small sample sizes could be written off, but if your model accurately predicts millions of brainstates based on nothing but the previous scan, we would have to find a new philosophy of free will.
Such accurate predictions as you describe in the OP will effectively rule out the entire left column of this chart:
| Indeterminism | Determinism | |
|---|---|---|
| Free Will | Libertarianism | Compatibilism |
| No Free Will | Hard Incompatibilism | Hard Determinism |
As mentioned by others, the difference between compatibilism and hard determinism is the semantic definition of free will. For me, determinism implies hard determinism with radical implications for moral culpability.
~Max