Someone who is able to apply Hobbes's decision-procedure and establish whether an action is just or not, has acquired the substance of civil science. Or so Hobbes comes very close to saying (De Corp., ch. 6, vii, E I 74). But the reasoning gone through in following the decisionprocedure is not reasoning from the properties of bodies politic to their causes. Indeed, the general notions of body, body politic, property of a body politic and generation of a property do not seem to come into it at all. So it is a question whether these notions are crucial to civil science. I think the answer is 'No' , but that this answer leaves a problem of interpretation. Hobbes seems to apply simultaneously two quite different conceptions of civil science, and it is not obvious how they go together.