Kepler belonged to the race of bleeders, the victims of emotional haemophilia, to whom every injury means multiplied danger, and who nevertheless must go on exposing himself to stabs and slashes. But one customary feature is conspicuously absent from his writings: the soothing drug of self-pity, which makes the sufferer spiritually impotent, and prevents his suffering from bearing fruit. He was a Job who shamed his Lord by making trees grow from his boils. In other words, he had that mysterious knack of finding original outlets for inner pressure; of transforming his torments into creative achievement, as a turbine extracts electric current out of the turbulent stream. His eye-deficiency seems the most perfidious trick that fate could inflict on a stargazer; but how is one to decide whether an inborn affliction will paralyse or galvanize? The myopic child, who sometimes saw the world doubled or quadrupled, became the founder of modern optics (the word "dioptries" on the oculist's prescription is derived from the title of one of Kepler's books); the man who could only see clearly at a short distance, invented the modern astronomical telescope. We shall have occasion to watch the working of this magic dynamo, which transforms pain into achievement and curses into blessings.
4. Appointment
He graduated from the Faculty of Arts at the University of Tuebingen at the age of twenty. Then, continuing on the road of his chosen vocation, he matriculated at the Theological Faculty. He studied there for nearly four years, but before he could pass his final examinations, fate intervened. The candidate of divinity was unexpectedly offered the post of a teacher of mathematics and astronomy in Gratz, capital of the Austrian province of Styria.
Styria was a country ruled by a Catholic Hapsburg prince and its predominantly Protestant Estates. Gratz accordingly had both a Catholic university and a Protestant school. When, in 1593, the mathematicus of the latter died, the Governors asked, as they often did, the Protestant university of Tuebingen to recommend a candidate. The Tuebingen senate recommended Kepler. Perhaps they wanted to get rid of the querulous young man, who had professed Calvinist views and defended Copernicus in a public disputation. He would make a bad priest but a good teacher of mathematics.
Kepler was taken by surprise and at first inclined to refuse – "not because I was afraid of the great distance of the place (a fear which I condemn in others) but because of the unexpected and lowly nature of the position, and my scant knowledge in this branch of philosophy". 10 He had never thought of becoming an astronomer. His early interest in Copernicus had been one among many others; it had been aroused, not by an interest in astronomy proper, but by the mystical implications of the suncentred universe.
Nevertheless, after some hesitations he accepted the offer – mainly, it seems, because it meant financial independence, and because of his inborn love of adventure. He made it a condition, however, that he should be allowed to resume his study of divinity at a later date – which he never did.
The new teacher of astronomy and "Mathematicus of the Province" – a title that went with it – arrived in Gratz in April 1594, at the age of twenty-three. A year later he hit on the idea which would dominate the rest of his life, and out of which his revolutionary discoveries were born.
I have so far concentrated on the emotional life of his childhood and adolescence. I must now briefly speak of his intellectual development. Here again, we have his self-portrait to guide us:
"This man was born destined to spend much time on difficult tasks from which others shrunk. As a boy he precociously attempted the science of versifying. He tried to write comedies and chose the longest poems to learn by heart... His efforts were at first devoted to acrostics and anagrams. Later on he set about various most difficult forms of lyric poetry, wrote a pindaric lay, dithyrambic poems and compositions on unusual subjects, such as the resting-place of the sun, the sources of rivers, the sight of Atlantis through the clouds. He was fond of riddles and subtle witticisms and made much play with allegories which he worked out to the most minute detail, dragging in far-fetched comparisons. He liked to compose paradoxes and ... loved mathematics above all other studies.
In philosophy he read the texts of Aristotle in the original... In theology he started at once on predestination and fell in with the Lutheran view of the absence of free will... But later on he opposed it... Inspired by his view of divine mercy, he did not believe that any nation was destined to damnation... He explored various fields of mathematics as if he were the first man to do so [and made a number of discoveries], which later on he found to have already been discovered. He argued with men of every profession for the profit of his mind. He jealously preserved all his writings and kept any book he could lay hands on with the idea that they might be useful at some time in the future. He was the equal of Crusius * in his attention to detail, far inferior to Crusius in industry, but his superior in judgment. Crusius collected facts, he analysed them; Crusius was a hoe, he a wedge..."
____________________
*
One of Kepler's teachers.
In his Horoscope he further reports that during his first year at the University he wrote essays on "the heavens, the spirits, the Genii, the elements, the nature of fire, the tides, the shape of the continents, and other things of the same kind".
The last remark about his student days reads:
"At Tuebingen I often defended the opinions of Copernicus in the disputation of the candidates, and I composed a careful disputation on the first motion, which consists in the rotation of the earth; then I was adding to this the motion of the earth around the sun for physical, or if you prefer, metaphysical reasons.
If there are living creatures on the moon (a matter about which I took pleasure in speculating after the manner of Pythagoras and Plutarch in a disputation written in Tuebingen in 1593), it is to be assumed that they should be adapted to the character of their particular country."
None of this points as yet in any definite direction. Indeed, his main complaint against himself, which he repeats over and over again, is his "inconsistency, thoughtlessness, lack of discipline and rashness"; his "lack of persistence in his undertakings, caused by the quickness of his spirit"; his "beginning many new tasks before the previous one is finished"; his "sudden enthusiasms which do not last, for, however industrious he may be, nevertheless he is a bitter hater of work"; his "failure to finish things he has begun".
Again we see that magic dynamo of the psyche at work. The streak of irresponsibility and restlessness in the blood, which turned his father, brother and uncles into vagabonds who could never settle down in any place or profession, drove Kepler into his unorthodox, often crankish intellectual enterprises, made him into the most reckless and erratic spiritual adventurer of the scientific revolution.
The lectures of this new teacher must have been quite an experience. He thought himself a poor pedagogue because, as he explains in his self-analysis, whenever he got excited – which was most of the time – he "burst into speech without having time to weigh whether he was saying the right thing". His "enthusiasm and eagerness is harmful, and an obstacle to him", because it continually leads him into digressions, because he always thinks of "new words and new subjects, new ways of expressing or proving his point, or even of altering the plan of his lecture or holding back what he intended to say". The fault, he explains, lies in his peculiar kind of memory which makes him promptly forget everything he is not interested in, but which is quite wonderful in relating one idea to another. "This is the cause of the many parentheses in his lectures when everything occurs to him at once and, because of the turmoil of all these images of thought in his memory, he must pour them out in his speech. On these grounds his lectures are tiring, or at any rate perplexing and not very intelligible."
No wonder that in his first year he had only a handful of students in his class, and in his second, none at all. Barely twelve months after his arrival in Gratz he wrote to his old teacher of astronomy in Tuebingen, Michael Maestlin, that he could not hope to last for another year, imploring
Maestlin to get him a job back at home. He felt unhappy, an exile from his sophisticated alma mater among the provincial Styrians. On his arrival, he had been promptly attacked by "Hungarian fever". Besides, religious tension was growing in the town, and made prospects even gloomier.
However, the directors of the school took a more optimistic view. In their report on the new teacher 11 they explained that the absence of students should not be blamed on him, "because the study of mathematics is not every man's affair". They made him give some additional lectures on Virgil and rhetorics "so that he should not be paid for nothing – until the public is prepared to profit from his mathematics too". The remarkable thing about their reports is their unmitigated approval not only of Kepler's intellect, but also of his character. He had "at first perorando, then docendo, and finally also disputando, given such account of himself that we cannot judge otherwise but that he is, in spite of his youth, a learned and in moribus a modest, and to this school of a respected Province a fitting magister and professor". This praise contradicts Kepler's own statement that the head of the school was his "dangerous enemy", because "I did not respect him sufficiently as my superior and disregarded his orders". 12 But young Kepler was as hypochondriacal about his relations to others as he was about his health.
5. Astrology
Another onerous duty, which he secretly enjoyed, during his four years in Gratz, was the publication of an annual calendar of astrological forecasts. This was a traditional obligation imposed on the official mathematicus in Styria and brought an additional remuneration of twenty florins per calendar – which Kepler direly needed at his miserable salary of a hundred and fifty florins per annum.
With his first calendar, Kepler was decidedly lucky. He had prophesied, among other things, a cold spell and an invasion by the Turks. Six months later he reported smugly to Michael Maestlin:
"By the way, so far the calendar's predictions are proving correct. There is an unheard-of cold in our land. In the Alpine farms people die of the cold. It is reliably reported that when they arrive home and blow their noses, the noses fall off... As for the Turks, on January 1 they devastated the whole country from Vienna to Neustadt, setting everything on fire and carrying off men and plunder." 13
The successful prophecies of the first calendar contributed more to the popularity of the new mathematicus than his enthusiastic and garbled lectures before an empty class-room. As always in times of crisis, belief in astrology was again on the increase in the sixteenth century, not only among the ignorant, but among eminent scholars. It played an important, and at times a dominant part in Kepler's life. His attitude to it was typical of the contradictions in his character, and of an age of transition.
He started his career with the publication of astrological calendars, and ended it as Court Astrologer to the Duke of Wallenstein. He did it for a living; with his tongue in his cheek, called astrology "the step-daughter of astronomy", popular prophecies "a dreadful superstition" and "a sortilegous monkeyplay". 14 In a typical outburst he wrote: "A mind accustomed to mathematical deduction, when confronted with the faulty foundations [of astrology] resists a long, long time, like an obstinate mule, until compelled by beating and curses to put its foot into that dirty puddle." 15
But while he despised these crude practices, and despised himself for having to resort to them, he at the same time believed in the possibility of a new and true astrology as an exact empirical science. He wrote a number of serious treatises on astrology as he would understand it, and the subject constantly intrudes even in his classic scientific works. One of these treatises carries, as a motto, "a warning to certain Theologians, Physicians and Philosophers ... that, while justly rejecting the stargazers' superstitions, they should not throw out the child with the bathwater." 16 For "nothing exists nor happens in the visible sky that is not sensed in some hidden manner by the faculties of Earth and Nature: [so that] these faculties of the spirit here on earth are as much affected as the sky itself." 17 And again: "That the sky does something to man is obvious enough; but what it does specifically remains hidden." 18 In other words, Kepler regarded the current astrological practices as quackery, but only to the extent to which a modern physician distrusts an unproven slimming diet, without doubting for a moment the influence o diet on health and figure. "The belief in the effect of the constellations derives in the first place from experience, which is so convincing that it can be denied only by people who have not examined it." 19
We have seen that in his self-analysis, in spite of its astoundingly modern introspective passages and acute characterizations of his family, all main events and character-attributes were derived from the planetary constellations. But on reflection, what other explanation was there available at the time? To a questing mind without an inkling of the processes by which heredity and environment shape a man's character, astrology, in one form or another, was the obvious means of relating the individual to the universal whole, by making him reflect the all-embracing constellation of the world, by establishing an intimate sympathy and correspondence between microcosmos and macrocosmos: "The natural soul of man is not larger in size than a single point, and on this point the form and character of the entire sky is potentially engraved, even if it were a hundred times larger." 20 Unless predestination alone were to account for everything, making further inquiry into the Book of Nature pointless, it was only logical to assume that man's condition and fate were determined by the same celestial motions which determine the weather and the seasons, the quality of the harvest, the fertility of animal and plant. In a word, astrological determinism, to a scientific mind like Kepler's, was the forerunner of biological and psychological determinism.
Already as a child he was fascinated by the problem: why he had become what he had become. We remember the passage in his self-analysis: "In theology I started at once on predestination and fell into the Lutheran view of the absence of free will". But he quickly repudiated it. When he was thirteen, "I wrote to Tuebingen asking that a certain theological treatise be sent to me, and one of my comrades upbraided me thus: 'Bachelor, does't thou too suffer from doubts about predestination?'" 21 The mystery of "why am I what I am?" must have been experienced with particular intensity by a precocious and unhappy adolescent in that century of awakening, when individual consciousness was emerging from the collective consciousness of the medieval beehive-hierarchy, where queens and warriors, workers and drones, had all inhabited their ordained cubby-holes in existence. But if there was no predestination, how was one to explain the differences in character and personality, talent and worth, between members of the same race, all descended from Adam; or between young Johannes himself, the infant prodigy, and his epileptic brother? Modern man has an explanation of sorts in terms of chromosomes and genes, adaptive responses and traumatic experiences; sixteenth-century man could only search for an explanation in the state of the universe as a whole at the moment of his conception or birth, as expressed by the constellation of earth, planets and stars.
The difficulty was to find out how exactly this influence worked. That "the sky does something to man" was self-evident; but specifically what? "Truly in all my knowledge of astrology I know not enough with certainty that I should dare to predict with confidence any specific thing." 21a Yet he never gave up hope:
"No man should hold it to be incredible / that out of the astrologers' foolishness and blasphemies / some useful and sacred knowledge may come / that out of the unclean slime / may come a little snail / or mussel / or oyster or eel, all useful nourishments; / that out of a big heap of lowly worms / may come a silk worm / and lastly / that in the evil-smelling dung / a busy hen may find a decent corn / nay, a pearl or a golden corn ./ if she but searches and scratches long enough." 22
There is hardly a page in Kepler's writings – some twenty solid volumes in folio – that is not alive and kicking.
And gradually, a vision did indeed emerge out of the confusion. At twenty-four, he wrote to a correspondent:
"In w
hat manner does the countenance of the sky at the moment of a man's birth determine his character? It acts on the person during his life in the manner of the loops which a peasant ties at random around the pumpkins in his field: they do not cause the pumpkin to grow, but they determine its shape. The same applies to the sky: it does not endow man with his habits, history, happiness, children, riches or a wife, but it moulds his condition..." 23
Thus only the pattern is cosmically determined, not any particular event; within that pattern, man is free. In his later years, this Gestalt concept of cosmic destiny became more abstract and purified from dross. The individual soul, which bears the potential imprint of the entire sky, reacts to the light coming from the planets according to the angles they form with each other, and the geometrical harmonies or disharmonies that result, just as the ear reacts to the mathematical harmonies of music, and the eye to the harmonies of colour. This capacity of the soul to act as a cosmic resonator has a mystic and a causal aspect: on the one hand it affirms the soul's affinity with the anima mundi, on the other, it makes it subject to strictly mathematical laws. At this point, Kepler's particular brand of astrology merges into his all-embracing and unifying Pythagorean vision of the Harmony of the Spheres.