# The Life of Isaac Newton

This is a reprint in the Cambridge Canto Classics series of an original from 1993. It is an abridged version of the full 900 page biography *Never at rest* that Westfall published in 1981 about the life and work of Isaac Newton. It leaves out most of the technical material, which includes much of the mathematics, and also the many footnotes are removed. All this to improve readability for a general readership. Hence, if you are mainly interested in his mathematical and physical results, this is not the primal place to find it. The man, more than his science, comes here to the foreground.

The book starts by sketching a sad, angry, and lonely childhood of Isaac Newton. His father died before Isaac was born as a premature on Christmas Day 1642 (according to the Julian Calendar that is). When he was three, his mother remarried, but his stepfather did not accept him so that he was left with his grandmother. He was always making things like kites, windmill models, and doll furniture. When he attended school he learned so easily that he could stay home most of the time. He attended from an age of 12 till 17 The King's School at Grantham where he got Latin, Greek and mathematics. He was somewhat disliked by the other students because he was 'strange' and so different, so intelligent. His family tried to set him at work at the farm at home, but he was clearly not suitable for that job, so he was sent back to school again.

Later (1664) he attended Trinity College, first as a kind of servant, but later, when he got a scholarship, as a proper student. He started a notebook known as "Questiones" (now published as *Questiones quaedam philosophicae*) in which he noted questions that arouse while he was studying natural philosophy (gravity, light, color, and atoms). The foundations of his mechanical theory, the optics, and the theory of fluxions, (the latter we now call calculus) were developed around 1665. The myth of the apple and of his *Anni Mirabilis* (the years 1665-6) when he returned to Woolsthorpe while Cambridge University closed down because of the plague, and he presumably returned to the university with a fully finished theory is definitely refuted by Westfall. However, he did a lot of studying on his own while he was away, which made him, in full anonymity, a scientist who was at the forefront of European knowledge of his time. His intelligence was recognized by Barrow, and Newton became his successor as the Lucasion professor in 1669.

Since he had to lecture and publish the text of his lectures, he chose as a subject *De analysis* which was not exactly mathematics, but optics in which he developed his theory of colors. In that period he also constructed a reflecting telescope, which, besides his mathematical skills pulled him from anonymity . His *Opticks* book was published in 1704.

In the autumn of 1675 Leibniz had obtained his alternative but equivalent approach to Newton's calculus. It is probable that Leibniz, via Collins, had seen some results of Newton's fluxion theory without proofs. Collins was, besides Barrow, an early supporter of Newton and was spreading the news. But Newton who preferred to retire in anonymity rather than to communicate may thus himself be partly responsible for his ignorance of what Leibniz was doing. A well known bitter priority dispute was the result. More details can be read in the book.

Then came a period wherein Newton was involved in alchemy, proper chemistry not yet existing. Westfall tries to find out why Newton got interested in this subject, but it remains unclear. Also theology caught Newton's attention since then. However, Newton cut down on his correspondence and retired in silence. Some manuscripts were sent to Halley (*De motu corporum in gyrium*) which, in a revised and extended version, formed the opening of his masterpiece that he embarked on around 1685: the *Philosophiæ naturalis principia mathematica* in which he gives a systematic axiomatic exposition of the laws of motion. Westfall devotes a whole chapter to it. Its publication certainly brought Newton officially and openly to the position of a leading European scientist. Shortly after, in 1693, Newton had a nervous breakdown, which is not fully explained although somewhat documented. Westfall assumes it was just exhaustion after finishing the *Principia*. It does mark the end of his most creative activity.

In 1696, eager to get away from research, Newton became the warden of the Royal Mint in London. Although the warden was not the head of the Mint (the master was), Newton engaged himself completely and became the de facto leader replacing the actual master. In 1705 he had already resigned from Cambridge University and from Trinity College, when he could apply his talent for management as the president of the Royal Society which he revived completely after a period of decline. At the end of his life new editions of the *Opticks* and of the *Principia* appeared in the midst of the turmoil of the Leibniz-Newton priority dispute. He also worked on manuscripts about the chronology of the origin of Western civilization that was only published posthumously (See Newton and the Origin of Civilization). He died on 20 March 1717 in London.

John Conduit husband of Newton's niece and his successor at the Royal Mint was in charge of Newton's legacy. Many of the quotes given by Westfall refer to Conduit, who of course was a first hand witness. However, when he reports on events from Newton's youth the testimonies are not very reliable as Westfall rightfully recognizes.

Since most of the technicalities are left out of the discussion here, there are only few illustrations: some graphs and at the beginning of the book a set of 6 grey-scale plates depicting portraits of Newton at different ages. So most of the pages form a compact bloc of text. Westfall's style is very readable tough but quite factual with only few anecdotes.

Of course there are many other books about Newton, the man and his work, (Westfall lists some of them, but there are of course also several more recent ones) and there is an awful lot of original historical material available. The full biography by Westfall of 1981 is and remains a major reference. With this abridged version, he made a careful selection so that it became accessible for a broader public that is not directly interested in an overload of the technical historical and scientific details. This reprint is an excellent introduction to Newton well beyond the many websites available about the man and his work.

**Submitted by Adhemar Bultheel |

**11 / May / 2016