Scientists could never discover that free will does not exist via scientific experimentation, because in a deterministic world, the result of the experiment would, itself, be determined. The conclusion that there is no such thing as free will would not be arrived at because the scientists chose to set up the experiment in a good way and reasoned correctly about the data they received. Instead, physics would determine both the study’s structure and conclusions. As such, the conclusion cannot be trusted.

Even if determinism is true, this truth would not be “discovered” by the experiment, but “determined.” Discovery requires the exercise of free will. That’s why all such experiments are self-defeating. They can only be informative if free will exists. And if the will must be free for the experiments to be informative, there is no point in doing the experiment. You already know the answer before you begin: free will exists.