There is a close connection between the assertion of natural rights and the theory of the social contract, or contract theory. The idea that the exercise of political power is legitimate only if it is founded on the consent of those who are subject to it (another of Locke’s theses), and thus that it is based on an agreement among those who decide to subject themselves to a higher power and with those to whom the exercise of power is entrusted, derives from the postulate that individuals possess rights not dependent on the institution of sovereignty and that the chief function of that institution is to allow the fullest possible realization of those rights compatible with secure social life. The connecting link between the doctrine of the rights of man and contract theory is the individualistic conception of society they hold in common: a conception according to which the particular individual, with his interests and needs, which take the form of rights in virtue of the acceptance of hypothetical law of nature, comes first and precedes the establishment of society. This contrasts with the organicist conception, in all its various guises, which takes the opposite view, seeing society as prior to the individual, or the social whole as taking precedence over its parts (in the Aristotelian formulation which had so enduring and influence). Modern contract theory is a real turning-point in the history of political thought, dominated as it had been by the organic idea, insofar as the contract theorists reversed the relationship between individual and society, and no longer saw society as a natural fact existing independently of the will of individuals, but as an artificial body, created by individuals in their own image and likeness to promote the satisfaction of their own interests and needs and the fullest exercise of their rights. The agreement which gives birth to the state is in turn viewed as possible, according to the theory of natural right, in virtue of the law of nature which attributes to all individuals certain natural rights that can be enjoyed only in the context of the free and ordered form of coexistence secured through such a voluntary accord-an accord requiring a mutual and reciprocal renunciation of certain rights on the part all the individuals concerned.
Without this Copernican revolution, which allowed the problem of the state to be viewed for the first time through the eyes of its subjects rather than its sovereign, the doctrine of the liberal sate, which is first and foremost the doctrine of juridical limits to state power, would have been impossible. Without individualism, there can be no liberalism.