As an explanation, I have taken elements of Ilaria Ramelli's scholarly account of the doctrine from her book
Part One – Origin of the term
Origen of Alexandria is regarded as the founder of the doctrine of universal salvation. He embedded it in his theory of apokatastasis, the restoration of all rational creatures to the Good (ie. God their Creator). However, there is evidence that he was not the first to use the term, and in his writings he refers to an already existing Christian tradition.
The Greek term apokatastasis was in use before Christianity, indicating a "restoration, reconstitution, return" to an original state and has a wide range of meanings – the recovery of health (medicine); the return of a hostage to his homeland (ethics); the re-establishment of atoms after a collision (physics), the apokatastasis of a heavenly body to its original position after a zodiacal revolution, or the return of the sun and the moon to visibility after an eclipse (astronomy).
To the Stoics, apokatastasis indicated the periodical return of the universe to its original condition, the completion of a cosmic cycle. Stoic cosmology was articulated in aeons or 'great years' that succeed one another; each of these aeons is identical, or almost identical, to all others, with the same events, the same people, and the same behaviours. The sequence of aeons continues forever. The end of an aeon is determined by a conflagration in which everything is resolved into the fire-aether-Logos (reason)-pneuma (breath, wind) that coincides with the supreme divinity (Zeus, Jupiter). The latter each time initiates a new expansion into a cosmos.
Origen criticised the Stoic concept for two main reasons:
1) it destroyed human free will by maintaining that everything that happens is repeated again and again and again by necessity;
2) by positing an infinity of the sequence of aeons, it did not imply an end or telos to which all of history points, but a senseless eternal repetition.
Origen explains apokatastasis in human terms as a return to or restoration of a condition that is proper and original to him her. He illustrates this general meaning by reference to the medical meaning, such as the resetting of a broken limb, or a healing generally; in politics it's the reintegration of an exile, in a military sense the readmission of a soldier into a unit from which he had been chased away.
All of these meanings can metaphorically be applied to the final restoration of all human beings or all rational creatures to God.
Part One – Origin of the term
Origen of Alexandria is regarded as the founder of the doctrine of universal salvation. He embedded it in his theory of apokatastasis, the restoration of all rational creatures to the Good (ie. God their Creator). However, there is evidence that he was not the first to use the term, and in his writings he refers to an already existing Christian tradition.
The Greek term apokatastasis was in use before Christianity, indicating a "restoration, reconstitution, return" to an original state and has a wide range of meanings – the recovery of health (medicine); the return of a hostage to his homeland (ethics); the re-establishment of atoms after a collision (physics), the apokatastasis of a heavenly body to its original position after a zodiacal revolution, or the return of the sun and the moon to visibility after an eclipse (astronomy).
To the Stoics, apokatastasis indicated the periodical return of the universe to its original condition, the completion of a cosmic cycle. Stoic cosmology was articulated in aeons or 'great years' that succeed one another; each of these aeons is identical, or almost identical, to all others, with the same events, the same people, and the same behaviours. The sequence of aeons continues forever. The end of an aeon is determined by a conflagration in which everything is resolved into the fire-aether-Logos (reason)-pneuma (breath, wind) that coincides with the supreme divinity (Zeus, Jupiter). The latter each time initiates a new expansion into a cosmos.
Origen criticised the Stoic concept for two main reasons:
1) it destroyed human free will by maintaining that everything that happens is repeated again and again and again by necessity;
2) by positing an infinity of the sequence of aeons, it did not imply an end or telos to which all of history points, but a senseless eternal repetition.
Origen explains apokatastasis in human terms as a return to or restoration of a condition that is proper and original to him her. He illustrates this general meaning by reference to the medical meaning, such as the resetting of a broken limb, or a healing generally; in politics it's the reintegration of an exile, in a military sense the readmission of a soldier into a unit from which he had been chased away.
All of these meanings can metaphorically be applied to the final restoration of all human beings or all rational creatures to God.