The Leviathan has been described as “original, persuasive, solid, coherent.” General commentaries on Hobbes usually single out his logic for special praise; more detailed critiques generally unearth a mass of confusions and inconsistencies. Confusions and inconsistencies there certainly are; more, I believe, than one would expect to find in the work of a man of such undeniable logical powers. Speculation upon the psychological explanation of this fact is intriguing, but no part of the purpose of the present article. It is part of my purpose, however, to contend that Hobbes's passion for clarity and certainty may have played a part in leading him to adopt perverse definitions, to which even he did not consistently adhere and which constituted a major source of confusion. Conversely, I disagree with those who say his analytical system is sound and only his empirical assumptions about human nature are open to serious criticism.
More specifically, one may profitably inquire whether there is some central concept that serves as a focal point for many of these difficulties. For example, it is often suggested, with merit, that Hobbes's perversion, or inversion, of the traditional meaning of “jus naturale” plays such a role. Without making any exclusive claim or denying the insights that may be gained by concentrating attention upon other focal points, my hypothesis is that understanding of Hobbes may be deepened by an examination of his use of the word “liberty.” I shall deal first with his definitions of the term, and then in turn with his applications of it to natural right and natural law, to sovereignty by acquisition, and finally to the social contract. I shall argue that his method, as illustrated by his definitions, leads him occasionally into confusion or inconsistency, and more frequently tends to confuse the reader and so to enable Hobbes to make an unsound conclusion appear sound, by means of specious reasoning. In particular, I shall contend that Hobbes's treatment of liberty (1) leads him into self-contradiction regarding the extent of natural liberty, (2) enables him to argue persuasively but speciously in support of the obligation to obey a sovereign who has attained his position by violence, and (3) prevents him from developing an acceptable theory of political obligation.