sir isaac newton -- 11/8/23
Today's selection -- from Science: A Four Thousand Year History by Patricia Fara. The myth of Newton’s falling apple:
“Apples are a favourite mythological fruit. In Don Juan, George Byron linked Newton's inspiration in a Lincolnshire orchard with Adam's temptation in the Garden of Eden:
“When Newton saw an apple fall, he found
In that slight startle from his contemplation …
A mode of proving that the earth turned round
In a most natural whirl called 'gravitation';
And this is the sole mortal who could grapple,
Since Adam, with a fall or with an apple.
“Newton originated this world-famous anecdote shortly before his death, reminiscing over a cup of tea with a younger friend, who reported that
‘the notion of gravitation ... was occasion'd by the fall of an apple, as he [Newton] sat in a contemplative mood. Why should that apple always descend perpendicularly to the ground, thought he to him self. Why should it not go sideways or upwards, but constantly to the earth's centre? Assuredly, the reason is, that the earth draws it ... there is a power, like that we here call gravity, which extends itself thro' the universe.’
“More than any other scientific myth, Newton's falling apple promotes the romantic notion that great geniuses make momentous discoveries suddenly and in isolation. His book on mechanics and gravity, first published in 1687, has come to symbolize the birth of mathematical science. Especially after the World War II, it was hailed as an international intellectual bible that would transcend religious differences, the product of a glorious scientific revolution ushering in the modern era. According to simplistic accounts of its impact, Newton founded modern physics by introducing gravity and simultaneously implementing two major transformations in methodology: unification and mathematization. By drawing a parallel between an apple and the Moon, he linked an everyday event on Earth with the motion of the planets through the heavens, thus eliminating the older, Aristotelian division between the terrestrial and celestial realms. As well as unifying the cosmos, Newton united mathematicians with natural philosophers, upstaging Descartes' Principia by making his own book a mathematical Principia--The Mathematical Principles of Natural Philosophy.
|Newton's own first edition copy of his Principia, with handwritten corrections for the second edition|
“Although Newton was undoubtedly a brilliant man, eulogies of a lone genius fail to match events. Like all innovators, he depended on the earlier work of Kepler, Galileo, Descartes, and countless others--as he remarked snidely to the disabled Hooke, 'I have seen further it is by standing on ye shoulders of giants.' Hailing him as the creator of modern science is also misleading. Far from being a dedicated physicist in today's sense, Newton searched for God by studying alchemy and the Bible as well as the natural world. And as a further complication, natural philosophers were not immediately converted to his ideas--Newton's model of the cosmos was repeatedly criticized and modified, so that today's Newtonianism is very different from the scheme he originally proposed in the Principia.
“The apple story was virtually unknown before Byron's time. Instead, Newton was symbolized by a comet, because he was glorified for imposing regularity on what were regarded as flaming meteors, sporadic warnings sent by God to awe a sinful world. When several comets appeared in the early 1860s--including the one now named after the astronomer Edmond Halley--Newton became obsessed by their behaviour, observing them with his own telescope, carrying out endless mathematical calculations, and engaging in vituperative correspondence with rivals such as Hooke and the Astronomer Royal. Secretive and reclusive, Newton was eventually persuaded into publication by Halley, who himself bore the printing costs of a momentous book that the Royal Society felt unable to afford.
“Newton deliberately made his Principia unsuitable for the mathematically faint-hearted: he wanted, he remarked, 'to avoid being baited by little Smatterers in Mathematicks.’ Writing in Latin to reach an international audience of experts, Newton went back to a classical language--geometry. By consolidating and developing the work of Galileo and others, he set out his three laws of motion, which describe how objects such as billiard balls or bullets move and interact. Newton then applied these laws to describe the motion of the planets and minute particles, introducing the new concept of gravity as a universal attractive force stretching out through space to affect comets, apples, and atoms in exactly the same way. Just as importantly, Newton expressed gravity's effects mathematically. According to his inverse square law, the closer two objects are, and the heavier, the more strongly they attract each other.
“Some mathematicians were immediately converted, but far more were bewildered. Amongst those who did understand, many were critical, and in response, Newton produced two further editions of his Principia (in 1713 and 1726), adding mathematical revisions and also--perhaps surprising to find in science's most famous book--explanations of God and the life-sustaining role of comets. Unlike Descartes, Newton visualized large tracts of empty space not only in the heavens but also between the tiny particles inside apparently solid matter. How, sceptics demanded to know, does gravity travel across the gaps? They accused Newton of bringing back old-fashioned occult forces that mechanical philosophers claimed to be eliminating. Still worse, gravity seemed to challenge God Himself. If gravitational power were somehow inherent in matter, then surely the clear distinction between brute matter and the spiritual world is blurred? The strongest and most enduring objections to Newton were based on religious arguments.”