Negative liberty is freedom from interference by other people. Negative liberty is primarily concerned with freedom from external restraint and contrasts with positive liberty (the possession of the power and resources to fulfil one's own potential). According to Thomas Hobbes, "a free man is he that in those things which by his strength and will he is able to do is not hindered to do what he hath the will to do" (Leviathan, Part 2, Ch. XXI; thus alluding to liberty in its negative sense).
An idea that anticipates the distinction between negative and positive liberty was G. F. W. Hegel's "sphere of right" (furthered in his Elements of the Philosophy of Right), which constitutes what now is called negative freedom and his subsequent distinction between "abstract" and "positive liberty." In the Anglophone tradition the distinction between negative and positive liberty was introduced by Isaiah Berlin in his 1958 lecture "Two Concepts of Liberty". According to Berlin, the distinction is deeply embedded in the political tradition. In Berlin's words, "liberty in the negative sense involves an answer to the question: 'What is the area within which the subject—a person or group of persons—is or should be left to do or be what he is able to do or be, without interference by other persons'." Restrictions on negative liberty are imposed by a person, not by natural causes or incapacity. Helvetius expresses the point clearly: "The free man is the man who is not in irons, nor imprisoned in a gaol, nor terrorized like a slave by the fear of punishment ... it is not lack of freedom, not to fly like an eagle or swim like a whale."
Frankfurt School psychoanalyst and humanistic philosopher Erich Fromm drew a similar distinction between negative and positive freedom in his 1941 work, The Fear of Freedom, that predates Berlin's essay by more than a decade. Fromm sees the distinction between the two types of freedom emerging alongside humanity's evolution away from the instinctual activity that characterizes lower animal forms. This aspect of freedom, he argues, "is here used not in its positive sense of 'freedom to' but in its negative sense of 'freedom from', namely freedom from instinctual determination of his actions." For Fromm, then, negative freedom marks the beginning of humanity as a species conscious of its own existence free from base instinct.