Here is a skeptical trilemma. We know that we are responsible. We do not know that determinism is false. Yet, if we do not know that determinism is false, we do not know that we are responsible. If we want to avoid the skeptical conclusion of rejecting the first claim, we ought to reject the third. It does not follow that compatibilism is true. But it follows that libertarianism, the view that we are responsible even though responsibility requires indeterminism, is (...) unknowable, at least for now. To see this, we need to compare different forms of skepticism and their response. (shrink)