In Chapter XV of Leviathan, his landmark work of political philosophy, Hobbes anticipates possible objections to his argument that, only by surrendering a portion of their freedom and accepting the rule of a sovereign Commonwealth, enforced by law, can mankind ensure a measure of security conducive to the preservation of life. He does so by framing these objections as the statements of a devil's advocate called the "Fool."

Here, the fool proposes a version of realpolitik, stating that reason is inconsistent with justice if one can benefit from breaking the law. He says,

being committed to his own care, there could be no reason, why every man might not do what he thought conduced thereunto: and . . . keep, or not keep covenants, when it conduced to one's benefit.

Hobbes refutes this argument in two ways. First, he says, our knowledge of future events is always imperfect and although one may get a lucky break and succeed or profit when transgressing the law, it's impossible to predict such a result well enough to have a sense of security in doing so. As he says, "such events do not make it reasonably or wisely done." Second, and speaking more to the fundamental argument of the book itself, he says, anyone thus breaking the law, who "declareth that he thinks he may with reason do so . . ." can only remain in any society that has united itself for peace and defense on the basis that such transgressions are never detected. Clearly, no one can reckon upon such perpetual blindess and stupidity as a source of their security. Given the probability that one will be "cast out of society . . ." upon detection, this is "consequently against the reason of (their) preservation . . . ." And, thus, it is justice, not injustice, that is consistent with reason, in being conducive to self-preservation.