John Philoponus

John Philoponus (s/; Ἰωάννης ὁ Φιλόπονος; c. 490 – c. 570), also known as John the Grammarian or John of Alexandria, was an Alexandrian philologist, Aristotelian commentator and Christian theologian, author of a considerable number of philosophical treatises and theological works. He is called as the originator of a most important theory of astronomy.

A rigorous, sometimes polemical writer and an original thinker who was controversial in his own time, John Philoponus broke from the Aristotelian–Neoplatonic tradition, questioning methodology and eventually leading to empiricism in the natural sciences. He was one of the first to propose a "theory of impetus" similar to the modern concept of inertia over Aristotelian dynamics.

Later in life Philoponus turned to Christian apologetics, arguing against the eternity of the world, a theory which formed the basis of pagan attacks on the Christian doctrine of Creation. He also wrote on Christology and was posthumously condemned as a heretic by the Imperial Church in 680–81 because of what was perceived as a tritheistic interpretation of the Trinity.

His by-name ὁ Φιλόπονος translates as "lover of toil", i.e. "diligent," referring to a miaphysite confraternity in Alexandria, the philoponoi, who were active in debating pagan (i.e. Neoplatonic) philosophers.

His posthumous condemnation limited the spread of his writing, but copies of his work did circulate in Greek or Latin versions in medieval Europe, influencing Bonaventure and Buridan. His work was also received in Arabic scholarly tradition, where he is known as Yaḥyā al-Naḥwī (i.e. "John the Grammarian"). His critique of Aristotle in the Physics commentary was a major influence on Giovanni Pico della Mirandola and Galileo Galilei, who cited Philoponus substantially in his works.[1][2]


Although Philoponus' originating from a Christian family is possible, nothing is known of his early life. Philoponus studied at the school of Alexandria and began publishing from about 510. He was a pupil and sometime amanuensis to the Neoplatonic philosopher Ammonius Hermiae, who had studied at Athens under Proclus.[3]

Philoponus' early writings are based on lectures given by Ammonius, but gradually he established his own independent thinking in his commentaries and critiques of Aristotle's On the Soul and Physics. In the latter work Philoponus became one of the earliest thinkers to reject Aristotle's dynamics and propose the "theory of impetus":[4] i.e., an object moves and continues to move because of an energy imparted in it by the mover and ceases the movement when that energy is exhausted. This insightful theory was the first step towards the concept of inertia in modern physics, although Philoponus' theory was largely ignored at the time because he was too radical in his rejection of Aristotle.

But this [view of Aristotle] is completely erroneous, and our view may be completely corroborated by actual observation more effectively than by any sort of verbal argument. For if you let fall from the same height two weights, one many times heavier than the other you will see that the ratio of the times required for the motion does not depend [solely] on the weights, but that the difference in time is very small. ... — John Philoponus' refutation of the Aristotelian claim that the elapsed time for a falling body is inversely proportional to its weight[5]

Philoponus is the only writer of antiquity to have formally presented such a concept. As the discovery of the principle of inertia is the hallmark achievement of modern science as it emerges in the 16th to 17th centuries, Pierre Duhem argues that its invention would put Philoponus among the "great geniuses of Antiquity" and the "principal precursors to modern science", although he holds it more likely that Philoponus may have received the idea from an earlier, otherwise unrecorded Alexandrian school of mechanics.[6]

In 529 Philoponus wrote his critique On the Eternity of the World Against Proclus in which he systematically defeats every argument put forward for the eternity of the world, a theory which formed the basis of pagan attack of the Christian doctrine of Creation. The intellectual battle against eternalism became one of Philoponus' major preoccupations and dominated several of his publications (some now lost) over the following decade.

He introduced a new period of scientific thought based heavily on three premises: (1) The universe is a product of one single God, (2) the heavens and the earth have the same physical properties, (3) and the stars are not divine.[7] With these principles Philoponus went after his rival, Simplicius of Cilicia, by questioning Aristotle's' view of dynamics and cosmology.[7] He argued that motion can occur in a void and that the velocity of a falling object is not based on its weight.[7] He also held that God created all matter with its physical properties and with natural laws that would allow matter to progress from a state of chaos to an organized state forming the present universe.[7] What remains of his writings indicate that he used the same didactic methods of reasoning that modern science uses and that he performed genuine experiments.[7]

The style of his commentaries and his conclusions made Philoponus unpopular with his colleagues and fellow philosophers, and he appears to have ceased his study of philosophy around 530, devoting himself to theology instead. Around 550 he wrote a theological work On the Creation of the World as a commentary on the Bible’s story of creation, using the insights of Greek philosophers and Basil the Great. In this work he transfers his theory of impetus to the motion of the planets, whereas Aristotle had proposed different explanations for the motion of heavenly bodies and for earthly projectiles. Thus Philoponus' theological work is recognized in the history of science as the first attempt at a unified theory of dynamics. Another of his major theological concerns was to argue that all material objects were brought into being by God (Arbiter, 52A–B).

Around 553 Philoponus made some theological contributions to the Council of Constantinople concerning Christology. His doctrine on Christ's duality, according to which in Christ remain two united substances, united but divided, is analogous to the union of the soul and body in human beings and coincides with the miaphysite school of thought. He also produced writings on the Trinity around this time. Arbiter, John Philoponus' Christological “opus magnum” stands in the line with St. Cyril of Alexandria and Severus of Antioch.[8] Philoponus asserted the understanding of Christ as divine and human, in opposition to Chalcedonian authors who strove to reach a middle ground.

Other Languages
العربية: يوحنا النحوي
azərbaycanca: İoann Filoponus
български: Йоан Филопон
català: Joan Filopò
čeština: Jan Filoponos
español: Juan Filópono
Esperanto: Johano Filopono
français: Jean Philopon
polski: Jan Filopon
português: João Filopono
română: Ioan Filopon
slovenčina: Ján Filoponos
slovenščina: Janez Filopon
srpskohrvatski / српскохрватски: Jovan Filopon
українська: Іоанн Філопон
Tiếng Việt: Joannes Philoponus