Write something unespected- something you didn't expect yourself to write. Break it open. Take a different angle. It's not like we'll suddenly stumble on the truth on selfhood, the whole point of selfhood is to create your own idea of it- and live it. Perhaps that's what troubles some ubermench wannabe's.
Thought is fuelled by experience.
It only excludes possibilities. It's destructive to an argument. Be open to thoughts constructed in different structures that your own. You'll need it to free yourself from the way you've been shaped. Discussing it over and over and insisting on discussing it on your own terms won't help you get any closer to discovering your free will.