<p>John Stuart Mill&#39;s classic has at its heart a brave (some might say Quixotic) attempt to define both the constraints on individual freedom, and the degree of coercion governments may legitimately use to limit that freedom. His solution is a 'very simple principle' - that one may coerce only to defend oneself or others from harm. This deceptively straightforward axiom has deep social consequences - it would, for example, ban all government intervention to make populations behave &#39;better&#39;. The resulting ramifications have been argued over by social scientists for more than 150 years, and never more so than in modern times.</p>