John Stuart Mill’s harm principle:
The harm principle holds that the actions of individuals should only be limited to prevent harm to other individuals. John Stuart Mill articulated this principle in On Liberty, where he argued that;
"The only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others."
An equivalent was earlier stated in France's Declaration of the Rights of Man and of the Citizen of 1789 as, "Liberty consists in the freedom to do everything which injures no one else; hence the exercise of the natural rights of each man has no limits except those which assure to the other members of the society the enjoyment of the same rights. These limits can only be determined by law."
The belief "that no one should be forcibly prevented from acting in any way he chooses provided his acts are not invasive of the free acts of others" has become one of the basic principles of libertarian politics.