Freedom, or the idea of being free, is a broad concept that has been given numerous interpretations by philosophies and schools of thought. The protection of interpersonal freedom can be the object of a social and political investigation, while the metaphysical foundation of inner freedom is a philosophical and psychological question.
The ama-gi, a Sumerian cuneiform word, is the earliest known written symbol representing the idea of freedom. The English word "freedom" comes from an Indo-European root that means "to love." Cognates of the English word "freedom" include the Old High German word for "peace" and the English word "afraid" from a Vulgar Latin word for breaking the peace.
Freedom as the absence of restraint means unwilling to subjugate, lacking submission, or without forceful inequality. The achievement of this form of freedom depends upon a combination of the resistance of the individual (or group) and one's (their) environment; if one is in jail or even limited by a lack of resources, this person is free within their power and environment, but not free to defy reality. Natural laws restrict this form of freedom; for instance, no one is free to fly (though we may or may not be free to attempt to do so). Isaiah Berlin appears to call this kind of freedom "negative freedom" — an absence of obstacles put in the way of action (especially by other people). He distinguishes this from "positive freedom", which refers to one's power to make choices leading to action.
Especially spiritually-oriented philosophers have considered freedom to be a positive achievement of human will rather than an inherent state granted at birth. Rudolf Steiner developed a philosophy of freedom based upon the development of situationally-sensitive ethical intuitions: "acting in freedom is acting out of a pure love of the deed as one intuits the moral concept implicit in the deed". Similarly, E. F. Schumacher held that freedom is an inner condition, and that a human being cannot "have" freedom, but "can make it his aim to become free". In this sense, freedom may also encompass the peaceful acceptance of reality. The theological question of freedom generally focuses on reconciling the experience or reality of inner freedom with the omnipotence of the divine. Freedom has also been used a rallying cry for revolution or rebellion.
In Hans Sachs' play Diogenes, the Greek philosopher says to Alexander the Great, whom he believes to be unfree: "You are my servants' servant". The philosopher states that he has conquered fear, lust, and anger - and is thus inwardly free - while Alexander still serves these masters - and despite his outward power has failed to achieve freedom; having conquered the world without, he has not mastered the world within. The self-mastery Sachs refers to here is dependent upon no one and nothing other than ourselves.
Notable 20th century individuals who have exemplified this form of freedom include Nelson Mandela, Rabbi Leo Baeck, Gandhi, Lech Wałęsa and Václav Havel.