Sam Harris and Daniel Dennett are determinists who agree that our thoughts and acts are completely determined by prior states of the universe and the laws of nature. But Harris is a hard determinist who thinks free will is simply an illusion while Dennett is a compatibilist who thinks we do have free will even though we are determined. In a review of Harris’ Free Will, Dennett says the book is veritable museum of mistakes. Harris replies with a lament that Dennett’s review is “a strange document—avuncular in places, but more generally sneering” and is itself a collection of distortions and mistakes. The review and reply are both lengthy, but a fairly quick look will give the student an idea of the differences between hard determinism and compatibilism.