" Tuebingen, January 28, 1605.
Although I have for several years neglected writing to you, your steadfast attachment, gratitude and sincere affection have not weakened but become rather stronger, albeit you have reached such a high step and distinguished position that you could, if you wished, look down on me... I do not wish to apologise further, and say only this: I have nothing of the same value to offer in writing to such an outstanding mathematician... I must further confess that your questions were sometimes too subtle for my knowledge and gifts, which are not of the same stature. Hence I could only keep silent... You will wait in vain for my criticism of your book on optics, which you request so urgently; it contains matters too lofty for me to permit myself to judge it... I congratulate you. The frequent and most flattering mention of my name [in that book] is a special proof of your attachment. But I fear that you credit me with too much. If only I were such as your praise makes me appear. But I understand only my modest craft." 4
And that was the end of it, though Kepler persisted in the onesided correspondence, and also in his miscellaneous requests – Maestlin should make inquiries about the suitor of Kepler's sister; Maestlin should find him an assistant, and so forth – which the old man steadfastly ignored.
The most detailed letters about the progress of the New Astronomy Kepler wrote to David Fabricius, a clergyman and amateur astronomer in Friesland. Some of these letters cover over twenty, and up to forty foolscap pages. Yet he could never persuade Fabricius to accept the Copernican view; and when Kepler informed him of his discovery of the First Law, Fabricius' reaction was:
"With your ellipse you abolish the circularity and uniformity of the motions, which appears to me the more absurd the more profoundly I think about it... If you could only preserve the perfect circular orbit, and justify your elliptic orbit by another little epicycle, it would be much better." 5
As for the patrons and wellwishers, they tried to encourage him, but were unable to comprehend what he was up to. The most enlightened among them, the physician Johannes Brengger, whose opinion Kepler particularly valued, wrote:
"When you say that you aim at teaching both a new physics of the sky and a new kind of mathematics, based not on circles but on magnetic and intelligent forces, I rejoice with you, although I must frankly confess that I am unable to imagine, and even less to comprehend, such a mathematical procedure." 6
This was the general reaction of Kepler's contemporaries in Germany. It was summed up by one of them:
"In trying to prove the Copernican hypothesis from physical causes, Kepler introduces strange speculations which belong not in the domain of astronomy, but of physics." 7.
Yet a few years later the same man confessed:
"I no longer reject the elliptical form of the planetary orbits and allowed myself to be persuaded by the proofs in Kepler's work on Mars." 8
The first to realize the significance and implications of Kepler's discoveries, were neither his German compatriots, nor Galileo in Italy, but the British: the traveller Edmund Bruce, the mathematician Thomas Harriot, tutor of Sir Walter Raleigh; the Reverend John Donne, the astronomical genius Jeremiah Horrocks, who died at twenty-one; and lastly, Newton.
3. Anticlimax
Delivered from his monumental labours, the usual anticlimax set in for Kepler.
He turned back to his persistent dream, the harmony of the spheres, convinced that the whole New Astronomy was merely a stepping-stone towards that ultimate aim in his "sweating and panting pursuit of the Creator's tracks". 9 He published two polemical works on astrology, a pamphlet on comets, another about the shape of snow crystals, conducted a voluminous correspondence on the true date of the birth of Christ. He continued with his calendars and weather predictions: on one occasion, when a violent thunder-storm darkened the sky at noon, as he had predicted a fortnight earlier, the people in the streets of Prague yelled, pointing at the clouds: "It's that Kepler coming."
He was by now an internationally famous scholar, a member of the Italian Accadémia dei Lincei (a forerunner of the Royal Socicty), but even more pleased about the distinguished society in which he moved in Prague:
"The Imperial Counsellor and First Secretary, Johann Polz, is very fond of me. [His wife and] the whole family are conspicuous here in Prague for their Austrian elegance and their distinguished and noble manners; so that it would be due to their influence if on some future day I made some progress in this respect, though, of course, I am still far away from it... Notwithstanding the shabbiness of my household and my low rank (for they are considered to belong to the nobility), I am free to come and go in their house as I please." 10
His rise in social status was reflected in the personalities of the godparents to the two children who were born to him in Prague: the wives of halberdiers to the first, Counts of the Palatinate and Ambassadors to the second. There was an endearing Chaplinesque quality about Kepler's efforts to display social graces: What a job, what an upheaval to invite fifteen to sixteen women to visit my wife in child-bed, to play host to them, to compliment them to the door!" 10a Though he wore fine cloth and Spanish ruffles, his salary was always in arrears: "My hungry stomach looks up like a little dog to its master who used to feed it." 11
Visitors to Prague were invariably impressed by his dynamic personality and quicksilvery mind; yet he was still suffering from lack of self-assurance – a chronic ill, on which success acted as a temporary sedative, but never as a complete cure. The turbulent times increased his feeling of insecurity; he lived in constant fear of penury and starvation, complicated by his obsessive hypochondria:
"You inquire after my illness? It was an insidious fever which originated in the gall and returned four times because I repeatedly sinned in my diet. On May 29 my wife forced me, by her pesterings, to wash, for once, my whole body. She immersed me in a tub (for she has a horror of public baths) with well heated water; its heat afflicted me and constricted my bowels. On May 31 I took a light laxative, according to habit. On June 1, I bled myself, also according to habit: no urgent disease, not even the suspicion of one, compelled me to do it, nor any astrological consideration... After losing blood, I felt for a few hours well; but in the evening an evil sleep threw me on my mattress and constricted my guts. Sure enough, the gall at once gained access to my head, bypassing the bowels... I think I am one of those people whose gallbladder has a direct opening into the stomach; such people are shortlived as a rule." 12
Even without hypochondria, there were sufficient reasons for anxiety. His imperial patron sat on a quaking throne – though, in truth, Rudolph rarely sat on it, preferring to hide from his odious fellow-creatures among his mechanical clocks and toys, gems and coins, retorts and alembics. There were wars and rebellions in Moravia and Hungary, and the treasury was empty. As Rudolph progressed from eccentricity to apathy and melancholia, his brother was depriving him piecemeal of his domains; in a word, Rudolph's final abdication was only a question of time. Poor Kepler, already expelled from his livelihood in Gratz, saw a second exile looming before him, and had to start once more pulling wires, stretching out feelers, and clutching at straws. But the Lutheran worthies in his beloved Wuerttemberg would have nothing to do with their enfant terrible, and Maximilian of Bavaria turned a politely deaf ear, as did other Princes whom he approached. The year after the publication of the New Astronomy saw him at his lowest ebb, unable to do any serious work, "my mind prostrate in a pitiful frost".
Then came an event which not only thawed it, but set it to bubble and boil.
4. The Great News
One day in March 1610, a certain Herr Johannes Matthaeus Wackher von Wackenfels, Privy Counsellor to his Imperial Majesty, Knight of the Golden Chain and of the order of St. Peter, amateur philosopher and poet, drove up in his coach to Kepler's house, and called for him in great agitation. When Kepler came down, Herr Wackher told him the news had just arrived at Court that a mathematician named Galileus in Padua had turned a Dutch spy-glass at the sky, and discovered
through its lenses four new planets in addition to the five which had always been known.
"I experienced a wonderful emotion while I listened to this curious tale. I felt moved in my deepest being... [Wackher] was full of joy and feverish excitement; at one moment we both laughed at our confusion, the next he continued his narrative and I listened intently – there was no end to it..." 13
Wackher von Wackenfels was twenty years older than Kepler, and devoted to him. Kepler sponged on the Privy Counsellor's excellent wine, and had dedicated to him his treatise on the snow crystals as a New Year's gift. Wackher, though a Catholic convert, believed in the plurality of worlds; accordingly, he thought that Galileo's discoveries were planets to other stars, outside our solar system. Kepler rejected this idea; but he equally refused to admit that the new heavenly bodies could be revolving round the sun, on the grounds that since there were only five perfect solids, there could only be six planets – as he had proved to his own satisfaction in the Cosmic Mystery. He accordingly deduced a priori, that what Galileo had seen in the sky could only be secondary satellites, which circled round Venus, Mars, Jupiter and Saturn, as the moon circled round the earth. Once again he had guessed nearly right for the wrong reasons: Galileo's discoveries were indeed moons, but all the four of them were moons of Jupiter.
A few days later, authentic news arrived in the shape of Galileo's short but momentous booklet, Sidereus Nuncius – The Messenger from the Stars. 14 It heralded the assault on the universe with a new weapon, an optic battering ram, the telescope.
VIII KEPLER AND GALILEO
1. A Digression on Mythography
IT was indeed a new departure. The range and power of the main sense organ of homo sapiens had suddenly started to grow in leaps to thirty times, a hundred times, a thousand times its natural capacity. Parallel leaps and bounds in the range of other organs were soon to transform the species into a race of giants in power – without enlarging his moral stature by an inch. It was a monstrously one-sided mutation – as if moles were growing to the size of whales, but retaining the instincts of moles. The makers of the scientific revolution were individuals who in this transformation of the race played the part of the mutating genes. Such genes are ipso facto unbalanced and unstable. The personalities of these "mutants" already foreshadowed the discrepancy in the next development of man: the intellectual giants of the scientific revolution were moral dwarfs.
They were, of course, neither better nor worse than the average of their contemporaries. They were moral dwarfs only in proportion to their intellectual greatness. It may be thought unfair to judge a man's character by the standard of his intellectual achievements, but the great civilizations of the past did precisely this; the divorce of moral from intellectual values is itself a characteristic development of the last few centuries. It is foreshadowed in the philosophy of Galileo, and became fully explicit in the ethical neutrality of modern determinism. The indulgence with which historians of science treat the Founding Fathers is based on precisely that tradition which the Fathers introduced – the tradition of keeping intellect and character as strictly apart as Galileo taught us to separate the "primary" and "secondary" qualities of objects. Thus moral assessments are thought to be essential in the case of Cromwell or Danton, but irrelevant in the case of Galileo, Descartes or Newton. However, the scientific revolution produced not only discoveries, but a new attitude to life, a change in the philosophical climate. And on that new climate, the personalities and beliefs of those who initiated it had a lasting influence. The most pronounced of these influences, in their different fields, were Galileo's and Descartes'.
The personality of Galileo, as it emerges from works of popular science, has even less relation to historic fact than Canon Koppernigk's. In his particular case, however, this is not caused by a benevolent indifference towards the individual as distinct from his achievement, but by more partisan motives. In works with a theological bias, he appears as the nigger in the woodpile; in rationalist mythography, as the Maid of Orleans of Science, the St. George who slew the dragon of the Inquisition. It is, therefore, hardly surprising that the fame of this outstanding genius rests mostly on discoveries he never made, and on feats he never performed. Contrary to statements in even recent outlines of science, Galileo did not invent the telescope; nor the microscope; nor the thermometer; nor the pendulum clock. He did not discover the law of inertia; nor the parallelogram of forces or motions; nor the sun spots. He made no contribution to theoretical astronomy; he did not throw down weights from the leaning tower of Pisa, and did not prove the truth of the Copernican system. He was not tortured by the Inquisition, did not languish in its dungeons, did not say "eppur si muove"; and he was not a martyr of science.
What he did was to found the modern science of dynamics, which makes him rank among the men who shaped human destiny. It provided the indispensable complement to Kepler's laws for Newton's universe: "If I have been able to see farther," Newton said, "it was because I stood on the shoulders of giants." The giants were, chiefly, Kepler, Galileo and Descartes.
2. Youth of Galileo
Galileo Galilei was born in 1564 and died in 1642, the year Newton was born. His father, Vincento Galilei, was an impoverished scion of the lower nobility, a man of remarkable culture, with considerable achievements as a composer and writer on music, a contempt for authority, and radical leanings. He wrote, for instance (in a study on counter-point):
"It appears to me that those who try to prove an assertion by relying simply on the weight of authority act very absurdly." 1
One feels at once the contrast in climate between the childhoods of Galileo and our previous heroes. Copernicus, Tycho, Kepler, never completely severed the navel-cord which had fed into them the rich, mystic sap of the Middle Ages. Galileo is a second-generation intellectual, a second-generation rebel against authority; in a nineteenth century setting, he would have been the Socialist son of a Liberal father.
His early portraits show a ginger-haired, short-necked, beefy young man of rather coarse features, a thick nose and conceited stare. He went to the excellent Jesuit school at the Monastery of Vallombrosa, near Florence; but Galileo senior wanted him to become a merchant (which was by no means considered degrading for a patrician in Tuscany) and brought the boy home to Pisa; then, in recognition of his obvious gifts, changed his mind and at seventeen sent him to the local university to study medicine. But Vincento had five children to look after (a younger son, Michelangelo, plus three daughters), and the University fees were high; so he tried to obtain a scholarship for Galileo. Although there were no less than forty scholarships for poor students available in Pisa, Galileo failed to obtain one, and was compelled to leave the University without a degree. This is the more surprising as he had already given unmistakable proof of his brilliance: in 1582, in his second year at the University, he discovered the fact that a pendulum of a given length swings at a constant frequency, regardless of amplitude. 2 His invention of the "pulsilogium", a kind of metronome for timing the pulse of patients, was probably made at the same time. In view of this and other proofs of the young student's mechanical genius, his early biographers explained the refusal of a scholarship by the animosity which his unorthodox anti-Aristotelian views raised. In fact, however, Galileo's early views on physics contain nothing of a revolutionary nature. 3 It is more likely that the refusal of the scholarship was due not to the unpopularity of Galileo's views, but of his person – that cold, sarcastic presumption, by which he managed to spoil his case throughout his life.
Back home he continued his studies, mostly in applied mechanics, which attracted him more and more, perfecting his dexterity in making mechanical instruments and gadgets. He invented a hydrostatic balance, wrote a treatise on it which he circulated in manuscript, and began to attract the attention of scholars. Among these was the Marchese Guidobaldo del Monte who recommended Galileo to his brother-in-law, Cardinal del Monte, who in turn recommended him to Ferdinand de Medici, the ruling Duke of Tuscany; as a
result, Galileo was appointed a lecturer in mathematics at the University of Pisa, four years after that same University had refused him a scholarship. Thus at the age of twenty-five, he was launched on his academic career. Three years later, in 1592, he was appointed to the vacant Chair of Mathematics at the famous University of Padua, again through the intervention of his patron, del Monte.
Galileo remained in Padua for eighteen years, the most creative and fertile years of his life. It was here that he laid the foundations of modern dynamics, the science concerned with moving bodies. But the results of these researches he only published towards the end of his life. Up to the age of forty-six, when the Messenger from the Stars was sent into the world, Galileo had published no scientific work. 4 His growing reputation in this period, before his discoveries through the telescope, rested partly on treatises and lectures circulated in manuscript, partly on his mechanical inventions (among them the thermoscope, a forerunner of the thermometer), and the instruments which he manufactured in large numbers with skilled artisans in his own workshop. But his truly great discoveries – such as the laws of motion of falling bodies and projectiles – and his ideas on cosmology, he kept strictly for himself and for his private correspondents. Among these was Johannes Kepler.
3. The Church and the Copernican System
The first contact between the two Founding Fathers took place in 1597. Kepler was then twenty-six, a professor of mathematics in Gratz; Galileo was thirty-three, a professor of mathematics in Padua. Kepler had just completed his Cosmic Mystery and, profiting from a friend's journey to Italy, had sent copies of it, among others, "to a mathematician named Galileus Galileus, as he signs himself". 5
Galileo acknowledged the gift in the following letter:
"Your book, my learned doctor, which you sent me through Paulus Amberger, I received not a few days but merely a few hours ago; since the same Paulus informed me of his impending return to Germany, I would be ungrateful indeed not to thank you at once: I accept your book the more gratefully as I regard it as proof of having been found worthy of your friendship. So far I have only perused the preface of your work, but from this I gained some notion of its intent, * and I indeed congratulate myself on having an associate in the study of Truth who is a friend of Truth. For it is a misery that so few exist who pursue the Truth and do not pervert philosophical reason. However, this is not the place to deplore the miseries of our century but to congratulate you on the ingenious arguments you found in proof of the Truth. I will only add that I promise to read your book in tranquility, certain to find the most admirable things in it, and this I shall do the more gladly as I adopted the teaching of Copernicus many years ago, and his point of view enables me to explain many phenomena of nature which certainly remain inexplicable according to the more current hypotheses. I have written [conscripsi] many arguments in support of him and in refutation of the opposite view – which, however, so far I have not dared to bring into the public light, frightened by the fate of Copernicus himself, our teacher, who, though he acquired immortal fame with some, is yet to an infinite multitude of others (for such is the number of fools) an object of ridicule and derision. I would certainly dare to publish my reflections at once if more people like you existed; as they don't, I shall refrain from doing so."