Negative liberty is defined as freedom from interference by other people and is primarily concerned with the possession of sociological agency. It contrasts with positive liberty (an individual's freedom from inhibitions of the social structure within the society such as classism, sexism, or racism) . According to Thomas Hobbes, "a free man is he that in those things which by his strength and wit he is able to do is not hindered to do what he hath the will to do" (Leviathan, Ch. XXI, [2], thus alluding to liberty in its negative sense).

The distinction between negative and positive liberty was drawn originally by Hegel^{[citation needed]}, but most famous in the anglophone tradition 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."

Sir Isaiah Berlin OM, FBA (6 June 1909 – 5 November 1997) was a British social and political theorist, philosopher and historian of ideas of Russian-Jewish origin, thought by many to be the dominant scholar of his generation. He excelled as an essayist, conversationalist and raconteur; and as a brilliant lecturer who improvised, rapidly and spontaneously, richly allusive and coherently structured material. He translated works by Ivan Turgenev from Russian into English and, during the war, worked for the British Diplomatic Service. In its obituary of the scholar, The Independent stated that "Isaiah Berlin was often described, especially in his old age, by means of superlatives: the world's greatest talker, the century's most inspired reader, one of the finest minds of our time ... there is no doubt that he showed in more than one direction the unexpectedly large possibilities open to us at the top end of the range of human potential".

In 1932, at the age of 23, he was elected to a prize fellowship at All Souls College, Oxford. From 1957 to 1967, he was Chichele Professor of Social and Political Theory at the University of Oxford. He was president of the Aristotelian Society from 1963 to 1964. In 1966, he played a crucial role in founding Wolfson College, Oxford, and became its first President. He was knighted in 1957, and was awarded the Order of Merit in 1971. He was President of the British Academy from 1974 to 1978. He also received the 1979 Jerusalem Prize for his writings on individual freedom. The annual Isaiah Berlin Lectures are held at the Hampstead Synagogue and both Wolfson College and the British Academy each summer. Berlin's work on liberal theory and on value pluralism has had a lasting influence.

Adam Curtis (born 1955) is a British BAFTA winning documentarian and a writer, television producer, director and narrator. He works for BBC Current Affairs.

Curtis was born in 1955. He attended the Sevenoaks School.

Curtis completed a Bachelor of Arts in Human Sciences at Mansfield College, University of Oxford, where he studied genetics, evolutionary biology, psychology, politics, anthropology and statistics. He started a Doctor of Philosophy and was a Tutor in Politics at the University of Oxford but became disillusioned with academia.

He left academia to make a career in television, obtaining a post on That's Life!, a programme that often placed serious and humorous content in close juxtaposition.

Curtis makes extensive use of archive footage in his documentaries. He has acknowledged the influence of recordings made by Erik Durschmied and to "constantly using his stuff in my films". An Observer profile said of Curtis' style:

The Observer adds "if there has been a theme in Curtis's work since, it has been to look at how different elites have tried to impose an ideology on their times, and the tragicomic consequences of those attempts."

Ronald Ernest "Ron" Paul (born August 20, 1935) is an American politician who has been the U.S. Representative for Texas's 14th congressional district, which includes Galveston, since 1997, and a three-time candidate for President of the United States, as a Libertarian in 1988 and as a Republican in 2008 and currently 2012. He is an outspoken critic of American foreign and monetary policies, including the Military–industrial complex and the Federal Reserve, and is known for his libertarian-leaning views, often differing from his own party on certain issues.

A native of Pittsburgh, Pennsylvania, Paul is a graduate of Gettysburg College and Duke University School of Medicine, where he earned his medical degree. He served as a medical officer in the United States Air Force from 1963 until 1968. He worked as an obstetrician-gynecologist from the 1960s to the 1980s, delivering more than 4,000 babies. He became the first Representative in history to serve concurrently with a child in the Senate when his son Rand Paul was elected to the United States Senate for Kentucky in 2010.