John Philoponus

“John Philoponus, also known as John the Grammarian or John of Alexandria, was a Byzantine Greek philologist from Alexandria, Aristotelian commentator, Christian theologian and an author of a considerable number of philosophical treatises and theological works. 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. He is also the historical founder of what is now called the Kalam cosmological argument.”

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“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’: 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.”

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“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.”