 Thus Hobbes apparently thinks that talk about incorporeal substances (such as Cartesian unextended thinking things) is just nonsense. But why does he think that? Hobbes’s comment about false affirmations suggests he thinks that ‘incorporeal substance’ is insignificant because ‘a substance is incorporeal’ is false. But that seems to derive the insignificance from the truth of materialism, which is hardly going to convince Hobbes’s opponents. Hobbes does offer a supporting argument, when he claims that ‘incorporeal substance’ and ‘incorporeal body’ are “all one”. But that premise too will be denied by his opponents, who think that there can be substances that are not bodies, and that ‘substance’ and ‘body’ are far from interchangeable terms.