同意理論是洛克政治義務理論的樞紐，也是自由主義政 治哲學的核心。洛克從自然法中找到自然權利，並以權利為基礎， 認定權利個體只對自己同意的政府或國家負有政治義務。政治義務 的同意形式有兩類：明示同意和默示同意，但洛克關於默示同意具 體形式的表述引發了諸多爭議。為解決這些挑戰，洛克在政治義務 的同意緯度之外，加入了自然法、功利主義、臣民身份等因素，但 這些補充不僅無法從根本上解決同意理論的困難，反而削弱了其政 治義務理論的同意緯度。洛克之所以陷入這樣一個吊詭困境，是因 為他所處的時代語境決定的---承諾性的自我作為自由主義的預 設，其本身是超驗性的，這種自我陷入現實政治運轉中必然難以支 撐全面的政治義務問題。

It is widely agreed that consent theory plays a central role in Locke’s political obligation, as well as in liberal political philosophy. Locke declares that natural rights, which stem from natural law, are the basis of political life, so that only consent of people can bring about political obligations to government or state. There are two kinds of consent: express consent and tacit consent. In order to solve the problem of express consent, Locke concentrates on the matter of tacit consent which leads to many controversy and criticism. To cope with these problems, Locke adds natural law, utilitarianism, citizenship to his doctrine of political obligation. However, instead of radically tackle the difficulty of consent theory，these supplements of political obligation weaken the foundation of consent theory. The paradox of Locke’s doctrine is due to the context of the times: Liberalism presupposes commitment self，which is transcendent. Once liberal self encounters complex political problems, it could not support full political obligation.