1. The Printing Press
At the dawn of the fifteenth century printing was no longer a novelty in Europe. Printing from wooden blocks on vellum, silk, and cloth apparently started in the twelfth century, and printing on paper was widely practised in the second half of the fourteenth. The blocks were engraved in relief with pictures or text or both, then thoroughly wetted with a brown distemper-like substance; a sheet of damp paper was laid on the block and the back of the paper was rubbed with a so-called frotton -- a dabber or burnisher -- until an impression of the carved relief was transferred to it. Each sheet could be printed on only one side by this method, but the blank backs of the sheets could be pasted together md then gathered into quires and bound in the same manner as manuscript-books. These 'block books' or xylographs circulated already in considerable numbers during Gutenberg's youth.
He was born in 1398 at Mainz and was really called Gensfleisch, meaning gooseflesh, but preferred to adopt the name of his mother's birthplace. The story of his life is obscure, highlighted by a succession of lawsuits against money-lenders and other printers; his claim to priority is the subject of a century-old controversy. But there exists a series of letters to a correspondent, Frère Cordelier, which has an authentic ring and gives a graphic description of the manner in which Gutenberg arrived at his invention. [1] Whether others, such as Costa of Haarlem, made the same invention at the same time or before Gutenberg is, from our point of view, irrelevant.
Oddly enough, the starting point of Gutenberg's invention was not the block-books -- he does not seem to have been acquainted with them -- but playing-cards. In his first letter to Cordelier he wrote:
For a month my head has been working; a Minerva, fully armed, must issue from my brain. . . . You have seen, as I have, playing-cards and pictures of saints. . . . These cards and pictures are engraved on small pieces of wood, and below the pictures there are words and entire lines also engraved. . . . A thick ink is applied to the engraving; and upon this a leaf of paper, slightly damp, is placed; then this wood, this ink, this paper is rubbed and rubbed until the back of the paper is polished. This paper is then taken off and you see on it the picture just as if the design had been traced upon it, and the words as if they had been written; the ink applied to the engraving has become attached to the paper, attracted by its softness and by its moisture. . . . Well, what has been done for a few words, for a few lines, I must succeed in doing for large pages of writing, for large leaves covered entirely on both sides, for whole books, for the first of all books, the Bible. . . . How? It is useless to think of engraving on pieces of wood the whole thirteen hundred pages. . . . What am I to do? I do not know: but I know what I want to do: I wish to manifold the Bible, I wish to have the copies ready for the pilgrimage to Aix la Chapelle.
Here, then, we have matrix or skill No. 1: the printing from wood-blocks by means of rubbing.
In the letters which follow we see him desperately searching for a simpler method to replace the laborious carving of letters in wood:
Every coin begins with a punch. The punch is a little rod of steel, one end of which is engraved with the shape of one letter, several letters, all the signs which are seen in relief on a coin. The punch is moistened and driven into a piece of steel, which becomes the 'hollow' or 'stamp'. It is into these coin-stamps, moistened in their turn, that are placed the little discs of gold, to be converted into coins, by a powerful blow.
This is the first intimation of the method of type-casting. It leads Gutenberg, by way of analogy, to the seal : 'When you apply to the vellum or paper the seal of your community, everything has been said, everything is done, everything is there. Do you not see that you can repeat as many times as necessary the seal covered with signs and characters?'
Yet all this is insufficient. He may cast letters in the form of coins, or seals, instead of engraving the wood, yet they will never make a clear print by the clumsy rubbing method; so long as his search remains confined to this one and only traditional method of making an 'imprint', the problem remains blocked. To solve it, an entirely different kind of skill must be brought in. He tries this and that; he thinks of everything under the sun: it is the period of incubation. When the favourable opportunity at last offers itself he is ready for it:
I took part in the wine harvest. I watched the wine flowing, and going back from the effect to the cause, I studied the power of this press which nothing can resist. . . .
At this moment it occurs to him that the same, steady pressure might be applied by a seal or coin -- preferably of lead, which is easy to cast -- on paper, and that owing to the pressure, the lead would leave a trace on the paper -- Eureka!
. . . A simple substitution which is a ray of light. . . . To work then! God has revealed to me the secret that I demanded of Him. . . . I have had a large quantity of lead brought to my home and that is the pen with which I shall write.
'The ray of light, was the bisociation of wine-press and seal -- which, added together, become the letter-press. The wine-press has been lifted out of its context, the mushy pulp, the flowing red liquid, the jolly revelry -- as Sultan's branch was wrenched out of the context of the tree -- and connected with the stamping of vellum with a seal. From now onward these separate skills, which previously had been as different as the butcher's, the baker's, and the candlestick-maker's, will appear integrated in a single, complex matrix:
One must strike, cast, make a form like the seal of your community; a mould such as that used for casting your pewter cups; letters in relief like those on your coins, and the punch for producing them like your foot when it multiplies its print. There is the Bible!
2. Gravity and the Holy Ghost
'If I have been able to see farther than others,' said Newton, 'it was because I stood on the shoulders of giants.' One of the giants was Johannes Kepler (1471-1530) whose three laws of planetary motion provided the foundation on which the Newtonian universe was built. They were the first 'natural laws' in the modern sense: precise, verifiable statements expressed in mathematical terms; at the same time, they represent the first attempt at a synthesis of astronomy and physics which, during the preceding two thousand years, had developed on separate lines.
Astronomy before Kepler had been a purely descriptive geometry of the skies. The motion of stars and planets had been represented by the device of epicycles and eccentrics -- an imaginary clockwork of circles turning on circles turning on circles. Copernicus, for instance, had used forty-eight wheels to represent the motion of the five known planets around the sun. These wheels were purely fictitious, and meant as such -- they enabled astronomers to make more or less precise predictions, but, above all, they satisfied the dogma that all heavenly motion must be uniform and in perfect circles. Though the planets moved neither uniformly nor in perfect circles, the imaginary cog-wheels did, and thereby 'saved the appearances'.
Kepler's discoveries put an end to this state of affairs. He reconciled astronomy with physics, and substituted for the fictitious clockwork a universe of material bodies not unlike the earth, freely floating and turning in space, moved by forces acting on them. His most important book bears the provocative title: A New Astronomy Based on Causation Or Physics of the Sky (1609). It contains the first and second of Kepler's three laws. The first says that the planets move around the sun not in cirdes but in elliptic orbits; the second says that a planet moves in its orbit not at uniform speed but at a speed that varies according to its position, and is defined by a simple and beautiful law: the line connecting planet and sun sweeps over equal areas in equal times. The third law establishes an equally elegant mathematical correlation between the length of a planet's year and its mean distance from the sun.
Kepler did not start his career as an astronomer, but as a student of theology (at the Lutheran University of Thuebingen); yet already as a student he was attracted by the Copernican idea of a sun-centred universe. Now Canon Copernicus's book, On the Revolutions of the Heavenly Spheres, had been published in the year of
his death, 1543; that is, fifty years before Kepler first heard of him; and during that half century it had attracted very little attention. One of the reasons was its supreme unreadabillty, which made it into an all-time worst-seller: its first edition of a thousand copies was never sold out. Kepler was the first Continental astronomer to embrace the Copernican theory. His Mysterium Cosmographicum, published in 1597 (fifty-four years after Copernicus's death), started the great controversy -- Galileo entered the scene fifteen years later.
The reason why the idea of a sun-centred universe appealed to Kepler was repeatedly stated by himself: 'I often defended the opinions of Copernicus in the disputations 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.' [2] I have emphasized the last words because they contain the leitmotif of Kepler's quest, and because he used the same expression in various passages in his works. Now what were those 'physical or, if you prefer, metaphysical reasons' which made Kepler prefer to put the sun into the centre of the universe instead of the earth?
My ceaseless search concerned primarily three problems, namely, the number, size, and motion of the planets -- why they are just as they are and not otherwise arranged. I was encouraged in my daring inquiry by that beautiful analogy between the stationary objects, namely, the sun, the fixed stars, and the space between them, with God the Father, the Son, and the Holy Ghost. I shall pursue this analogy in my future cosmographical work. [3]
Twenty-five years later, when he was over fifty, Kepler repeated his credo: 'It is by no means permissible to treat this analogy as an empty comparison; it must be considered by its Platonic form and archetypal quality as one of the primary causes.'
He believed in this to the end of his life. Yet gradually the analogy underwent a significant change:
The sun in the middle of the moving stars, himself at rest and yet the source of motion, carries the image of God the Father and Creator. He distributes his motive force through a medium which contains the moving bodies, even as the Father creates through the Holy Ghost. [4]
Thus the 'moving bodies' -- that is, the planets -- are now brought into the analogy. The Holy Ghost no longer merely fills the space between the motionless sun and the motionless fixed stars. It has become an active force, a vis motrix, which drives the planets. Nobody before Kepler had postulated, or even suspected, the existence of a physical force acting between the sun and the planets. Astronomy was not concerned with physical forces, nor with the causes of the heavenly motions, merely with their description. The passages which I have just quoted are the first intimation of the forthcoming marriage between physics and astronomy -- the act of betrothal, as it were. By looking at the sky, not through the eyes of the geometrician only, but of the physicist concerned with natural causes, he hit upon a question which nobody had asked before, The question was: 'Why do the planets closer to the sun move faster than those which are far away? What is the mathematical relation between a planet's distance from the sun and the length of its year?'
These questions could only occur to one who had conceived the revolutionary hypothesis that the motion of the planet -- and therefore its velocity and the duration of its year -- was governed by a physical force emanating from the sun. Every astronomer knew, of course, that the greater their distance from the sun the slower the planets moved. But this phenomenon was taken for granted, just as it was taken for granted that boys will be boys and girls will be girls, as an irreducible fact of creation. Nobody asked the cause of it because physical causes were not assumed to enter into the motion of heavenly bodies. The greatness of the philosophers of the scientific revolution consisted not so much in finding the right answers but in asking the right questions; in seeing a problem where nobody saw one before; in substituting a why for a how.
Kepler's answer to the question why the outer planets move slower than the inner ones, and how the speed of their motion is related to their distance from the sun, was as follows:
There exists only one moving soul in the centre of all the orbits; that is the sun which drives the planets the more vigorously the closer the planet is, but whose force is quasi-exhausted when acting on the outer planets because of the long distance and the weakening of the force which it entails. [5]
Later on he commented:
If we substitute for the word "soul" the word "force", then we get just the principle which underlies my Physics of the Skies. As I reflected that this cause of motion diminishes in proportion to distance just as the light of the sun diminishes in proportion to distance from the sun, I came to the conclusion that this force must be substantial -- "substantial" not in the literal sense but . . . in the same manner as we say that light is something substantial, meaning by this an unsubstantial entity emanating from a substantial body. [6]
We notice that Kepler's answer came before the question -- that it was the answer that begot the question. The answer, the starting point, was the analogy between God the Father and the sun -- the former acting through the Holy Ghost, the latter through a physical force. The planets must obey the law of the sun -- the law of God -- the mathematical law of nature; and the Holy Ghost's action through empty space diminishes, as the light emanating from the sun does, with distance. The degenerate, purely descriptive astronomy which originated in the period of the Greek decline, and continued through the Dark and Middle Ages until Kepler, did not ask for meaning and causes. But Kepler was convinced that physical causes operate between heavenly, just as between earthy, bodies, and more specifically that the sun exerts a physical force on the planets. It was this conviction which enabled him to formulate his laws. Physics became the auxiliary matrix which secured his escape from the blocked situation into which astronomy had manoeuvred itself.
The blockage -- to cut a very long story short -- was due to the fact that Tycho de Brahe had improved the instruments and methods of star-gazing, and produced observational data of a hitherto unequalled abundance and precision; and the new data did not fit into the traditional schemes. Kepler, who served his apprenticeship under Tycho, was given the task of working out the orbit of Mars. He spent six years on the task and covered nine thousand folio-sheets with calculations in his small handwriting without getting anywhere. When at last he believed he had succeeded he found to his dismay that certain observed positions of Mars differed from those which his theory demanded by magnitudes up to eight minutes arc. Eight minutes arc is approximately one-quarter of the apparent diameter of the moon. This was a catastrophe. Ptolemy, and even Copernicus, could afford to neglect a difference of eight minutes, because their observations were accurate only within a margin of ten minutes, anyway. 'But,' Kepler wrote in the New Astronomy, 'but for us, who by divine kindness were given an accurate observer such as Tycho Brahe, for us it is fitting that we should acknowledge this divine gift and put it to use. . . . Henceforth I shall lead the way towards that goal according to my ideas. For if I had believed that we could ignore these eight minutes, I would have patched up my hypothesis accordingly. But since it was not permissible to ignore them, those eight minutes point the road to a complete reformation of astronomy. . . .' [7]
Thus a theory, built on years of labour and torment, was instantly thrown away because of a discord of eight miserable minutes arc. Instead of cursing those eight minutes as a stumbling block, he transformed them into the cornerstone of a new science. For those eight minutes arc had at last made him realize that the field of astronomy in its traditional framework was well and truly blocked.
One of the recurrent frustrations and tragedies in the history of thought is caused by the uncertainty whether it is possible to solve a given problem by traditional methods previously applied to problems which seem to be of the same nature. Who can say how many lives were wasted and good minds destroyed in futile attempts to square the circle, or to construct a "perpetuum mobile"? The proof that these pro
blems an insoluble was in each case an original discovery in itself (such as Maxwell's second law of thermodynamics); and such proofs could only be found by looking at the problem from a point of view outside its traditional matrix. On the other hand, the mere knowledge that a problem is soluble means that half the game is already won.
The episode of the eight minutes arc had convinced Kepler that his problem -- the orbit of Mars -- was insoluble so long as he felt bound by the traditional rules of sky-geometry. Implied in those rules was the dogma of 'uniform motion in perfect circles'. Uniform motion he had already discarded before the crisis; now he felt that the even more sacred one of circular motion must also go. The impossibility of constructing a circular orbit which would satisfy all existing observations suggested to him that the circle must be replaced by some other curve.
The conclusion is quite simply that the planet's path is not a circle -- it curves inward on both sides and outward again at opposite ends. Such a curve is called an oval. The orbit is not a circle but an oval figure. [8]
This oval orbit was a wild, frightening new departure for him. To be fed up with cycles and epicycles, to mock the slavish imitators of Aristotle was one thing; to assign an entirely new, lopsided, implausible path for the heavenly bodies was quite another. Why indeed an oval? There is something in the perfect symmetry of spheres and circles which has a deep, reassuring appeal to the unconscious mind -- otherwise it could not have survived two millennia. The oval lacks that archetypal appeal. It has an arbitrary, distorted form. It destroyed the dream of the 'harmony of the spheres', which lay at the origin of the whole quest. At times he felt like a criminal, or worse: a fool. All he had to say in his own defence was: 'I have cleared the Augean stables of astronomy of cycles and spirals, and left behind me only a single cartful of dung.' [9]
The Act of Creation Page 13