Hobbes prefaces Leviathan with a letter in which he dedicates the work to Francis Godolphin and at the same time offers him a summary of the theory of public authority contained in the book. ‘I speak’, Hobbes explains, ‘not of the men, but (in the Abstract) of the Seat of Power.’ This seat, he adds in his Introduction, is occupied by ‘that great LEVIATHAN called a COMMON-WEALTH, or STATE’. The essence of Hobbes's theory of public power is thus that the person identifiable as the true ‘subject’ of sovereignty in any lawful state must be the person of the state itself.

Hobbes's opening remarks allude to what has proved to be one of the most enduring puzzles in our inherited theories of government. On the one hand, most contemporary political philosophers would agree with Hobbes that the state is the seat of sovereignty. As Hobbes expresses the claim later in Leviathan, it is ‘the Reason of this our Artificiall Man the Common-wealth, and his Command, that maketh Law’, so that civil law is nothing other than ‘the Will and Appetite of the State’. But on the other hand, most contemporary philosophers would also agree with Hobbes when he adds that the state amounts to nothing more than an artifice. To quote Hobbes's way of expressing this further point, the state has no capacity ‘to doe any thing’; it is ‘but a word, without substance, and cannot stand’. There, then, is the puzzle.