Contributor(s): Quentin Skinner | Among contemporary political theorists, the idea of individual liberty is generally defined in negative terms as absence of interference. This lecture argues that, if the concept is instead approached genealogically, this orthodoxy begins to appear in need of qualification and perhaps abandonment. The genealogy traced in the lecture is shown to carry three specific implications, which are discussed in turn. The first is that the concept of interference is of much greater complexity than is often allowed, and gives rise to a number of rival theories of negative liberty. The second is that it may be misleading to assume that liberty can be defined only in negative terms. Finally, even if we accept that liberty is a negative concept, it remains unclear that negative liberty is best understood as absence of interference. The lecture ends by considering the rival 'republican' contention that freedom is best understood as a condition of independence from the arbitrary will and power of others. Quentin SkinnerQuentin Skinner is the Barber Beaumont Professor of the Humanities at Queen Mary, University College London. He is the author of numerous books and articles on early modern political thought and is a founder of the ‘Cambridge School’ of the history of political thought.