Does the free will exist? No present research provides any evidence for or against. The idea that the free will does not exist is based on a lack of understanding how complex dynamical systems like the brain work.
Where are the limits of the body?
Where does your body end? All fairly clear to you, but not to your brain. A tool you hold in your hand is a part of your body, and sometimes a rubber hand can seem like your real hand. How can this be?