Imagine a small machine with 1 light & 1 button. The light turns on briefly exactly 1 second BEFORE the button is pressed. Proving that no one has free will to push button when want. After playing w/ machine, what % of people would refuse to eat, & so have to be hospitalized?
With enough individual training data, it should be possible to predict the button press seconds before it happens, because our brains are quite deterministic. But reacting to the light to stop yourself takes only about 200ms, and we may come up with tricks that add another 100?