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April 22, 2016

Isaac Newton, Number One Ok Smart Guy

Until close to Newton’s time, the stars had been accepted as a fixed background to the motions of the Earth and the rest of the solar system. The idea developed that they might be bodies like our sun, but even through a telescope they still looked like luminous points, revealing nothing of their size. Newton found a way to tackle this problem (System 596). He noted that a prominent (first magnitude) star looked about as bright as Saturn. He knew how far away Saturn is; and also knew that we see Saturn by the sunlight that it scatters back towards us. Given that the intensity of light from a source falls off as the inverse square of the distance, he could calculate how far away a star like our sun would have to be to look as bright by direct radiation as Saturn does by reflected light. His result, expressed in modern terms, was about ten lightyears, which is absolutely of the right order of magnitude.”

A.P. French, “”Isaac Newton, Explorer of the Real World,” pp. 50-77, in Stayer, Marcia Sweet, ed., Newton’s Dream. Montreal, CA: MQUP, 1988.

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August 18, 2015

Newton’s non-clockwork universe

The New Atlantis has just published five essays exploring “The Unknown Newton”. It is — bless its heart! — open access. Here’s the table of contents:

Rob Iliffe provides an overview of Newton’s religious thought, including his radically unorthodox theology.

William R. Newman examines the scientific ambitions in Newton’s alchemical labors, which are often written off as deviations from science.

Stephen D. Snobelen — who in the course of writing his essay discovered Newton’s personal, dog-eared copy of a book that had been lost — provides an in-depth look at the connection between Newton’s interpretation of biblical prophecy and his cosmological views.

Andrew Janiak explains how Newton reconciled the apparent tensions between the Bible and the new view of the world described by physics.

Finally, Sarah Dry describes the curious fate of Newton’s unpublished papers, showing what they mean for our understanding of the man and why they remained hidden for so long.

Stephen Snobelen’s article, “Cosmos and Apocalypse,” begins with a paper in the John Locke collection at the Bodelian: Newton’s hand-drawn timeline of the events in Revelations. Snobelen argues that we’ve read too much of The Enlightenment back into Newton.

In particular, the concept of the universe as a pure clockwork that forever operates according to mechanical laws comes from Laplace, not Newton, says Snobelen. He refers to David Kubrin’s 1967 paper “Newton and the Cyclical Cosmos“; it is not open access. (Sign up for free with Jstor and you get constrained access to its many riches.) Kubrin’s paper is a great piece of work. He makes the case — convincingly to an amateur like me — that Newton and many of his cohorts feared that a perfectly clockwork universe that did not need Divine intervention to operate would be seen as also not needing God to start up. Newton instead thought that without God’s intervention, the universe would wind down. He hypothesized that comets — newly discovered — were God’s way of refreshing the Universe.

The second half of the Kubrin article is about the extent to which Newton’s late cosmogeny was shaped by his Biblical commitments. Most of Snobelen’s article is about a discovery in 2004 of a new document that confirms this, and adds to it that God’s intervention heads the universe in a particular direction:

In sum, Newton’s universe winds down, but God also renews it and ensures that it is going somewhere. The analogy of the clockwork universe so often applied to Newton in popular science publications, some of them even written by scientists and scholars, turns out to be wholly unfitting for his biblically informed cosmology.

Snobelen attributes this to Newton’s recognition that the universe consists of forces all acting on one another at the same time:

Newton realized that universal gravity signaled the end of Kepler’s stable orbits along perfect ellipses. These regular geometric forms might work in theory and in a two-body system, but not in the real cosmos where many more bodies are involved.

To maintain the order represented by perfect ellipses required nudges and corrections that only a Deity could accomplish.

Snobelen points out that the idea of the universe as a clockwork was more Leibniz’s idea than Newton’s. Newton rejected it. Leibniz got God into the universe through a far odder idea than as the Pitcher of Comets: souls (“monads”) experience inhabiting a shared space in which causality obtains only because God coordinatis a string of experiences in perfect sync across all the monads.

“Newton’s so-called clockwork universe is hardly timeless, regular, and machine-like,” writes Snobelen. “[I]nstead, it acts more like an organism that is subject to ongoing growth, decay, and renewal.” I’m not sold on the “organism” metaphor based on Snobelen’s evidence, but that tiny point aside, this is a fascinating article.

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August 17, 2015

Newton was not an astrologer

I got a little interested in the question of Isaac Newton’s connection to astrology because of something I’ve been working about casuality. After all, Newton pursued alchemical studies with great seriousness. And he gave us a theory of action at a distance that I thought might be taken as providing a rationale for astrological effects.

But, no. According to a post by Graham Bates:

In a library of 1763 books, (1752 different titles excluding duplicates) he had 369 books on what we would call scientific subjects, plus 169 on Alchemy (including many of the important texts on the subject copied in his own hand), there were also 477 books on Theology. He possessed only four books on astrology; two of these were treatises on astrology, one was an almanac, and one was a refutation of astrology

Bates says that a book on astrology that he purchased as a boy led him to learn about Euclid’s theorems so he could construct an astrologocial chart, but that is the extent of his known interest.

Bates also does a good job tracking down a spurious quote:

There is a story, much quoted in astrological articles and books, about a dispute between Newton and Halley (of the comet fame), supposedly about astrology, in which Newton replies to a remark by Halley “I have studied these things, you have not”.

The actual quote refers to theology, not astrology. So, no, Newton was not practitioner of astrology and there’s no reason to think that he gave it any credence. (Me neither, by the way.)

The post is on the Urania Trust site, which I had not heard of before. The group was founded in 1970 “to further the advancement of education by the teaching of the relationship between main’s [sic] knowledge of, beliefs about, the heavens and every aspect of his art science philosophy and religion.” Given its commitment to taking astrology seriously, the fairness of its post about Newton is admirable.

(Now if I could only find out if Newton played billiards.)

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