Galileo Overthrows Ancient Philosophy
جاليلو يسقط ( يقلب ) الفلسفة القديمة
Author: Lodge, Sir Oliver
المُؤلف: السّير أوليفير لودج
Galileo Overthrows Ancient Philosophy
The Telescope and Its Discoveries, A.D. 1610
When the Copernican system of astronomyنظام كوبرنيكس فى علم الفضاء was published to the world (1543) it had to encounterيواجه , as all capital theoriesالنظريات الرئيسية and discoveries in science have done, the criticism, and, for some time, the oppositionالمعاكس , of men holding other views. After Copernicus, the next great name in modern science is that of Tycho Brahe (1546-1601), who rejected the theory of Copernicus in favor of a modified form of the Ptolemaic systemالنظام البطلمى . This was still taught in the schools when two mighty أقوياء contemporaries عصرى, geniuses of science, rose يأتى بشكل موازى to overthrow it forever. للأبد These men were Galileo Galilei – commonlyشائع known as Galileo - and Kepler, both astronomers, though Galileo's scientific work covered also a much wider fieldمجال أوسع . He is regarded أخذ بعين الإعتبارto-day as markingعلامة a distinct مميزepochدور in the progressتقدم of the world, and the following account of his work by the eminent scientist عالم بارز , Sir Oliver Lodge, expressesيعبر عن no more than a just appreciation إعجاب of his great services to mankind . البشرية Galileo exercisedتدرب a vast influenceنفوذ واسع on the development of human thoughtالفكر الإنسانى . A man of great and wide culture, a so-calledيسمى universal geniusالعبقرى العالمى , it is as an Experimentalتجريبى philosopher that he takes the first rankالرتبة الأولى . In this capacityمقدرة he must be placed alongsideبجانب of Archimedesأرشميدس , and it is pretty certainمؤكد that between the two there was no man of magnitudeأهمية equal to either in experimental philosophy. It is perhaps too boldجرىء a speculationتأمل , but I ventureيغامر to doubt whether in succeeding generationsنجاح الأجيال we find his equal in the domainميدان of purely experimental science until we come to Faradayفاراداى . Faraday was no doubt his superiorأعلى منزلة , but I know of no other of whom the like can unhesitatinglyبلا تردد be said. In mathematical and deductive scienceالعلم الإستدلالى , of course, it is quite otherwise. Kepler, for instance, and many men before and since, have far excelledيتفوق على Galileo in mathematical skill and power, though at the same time his achievementsإنجاز in this department are by no means to be despised. يحتقر Born ولد at Pisa on the very day that Michelangeloمايكل أنجلو lay dying in Rome, he inheritedورث from his father a noble name, cultivated tastesالمذاق المهذب , a keenمهتم love of truth, and an impoverishedأفقر patrimonyميراث . Vincenzo de Galilei, a descendantسليل of the important Bonajuti family, was himself a mathematicianرياضى and a musician, and in a book of his still extantموجود he declares himself in favor of free and open inquiryإستعلام into scientific mattersrقضايا , unrestrainedغير مقيد by the weight of authority and tradition. In all probability the son imbibedيتشرب these preceptsوصايا : certainly he acted on them. Vincenzo, having himself experienced the unremunerativeغير مربح character of scientific work, had a horror of his son's taking to it, especially as in his boyhood فترة الشباب he was always constructing ingeniousمبدع mechanical toys and exhibiting other marks of precocityمبكر. So the son was destinedإتجه إلى for business - to be, in fact, a cloth-dealer. But he was to receive a good education first, and was sent to an excellent conventمدرسة للراهبات school. Here he made rapid progressتقدم سريع , and soon excelled in all branches of classicsالآثار الأدبية and literature. He delighted مبتهجin poetry, and in later years wrote several essays on Danteدانتى , Tassoتاسو , and Ariostoأريوستو , besides composingتكوين some tolerableمحتمل poemsقصائد himself. He played skillfullyبارع on several musical instrumentsأدوات , especially on the luteالعود , of which indeed he became a master, and on which he solacedسلى himself when quite an old man. Besides this, he seems to have had some skill as an artist, which was useful afterwardفيما بعد in illustratingتوضيح his discoveries, and to have had a fine sensibilityوعى as an art criticناقد فنى , for we find several eminentبارز painters of that day acknowledgingالتسليم بصحة the value of the opinion of the young Galileo. Perceivingإدراك all this display of ability, the father wisely بحكمةcame to the conclusionإستنتاج that the selling of woollenصوفى stuffs قماش would hardly satisfy his aspirations طموحfor long, and that it was worthجدير a sacrifice to send him to the university. So to the university of his native town he went, with the avowed إعترف object of studying medicine, that careerمهنة seeming the most likely to be profitableمربح . Old Vincenzo's horror of mathematics or science as a means of obtaining a livelihoodالرزق – المعيشة is justified by the fact that while the universityprofessor of medicine received two thousand scudi a year, the professor of mathematics had only sixty; that is thirteen pounds a year, or seven and a half pence a day. So the son had been kept properly ignorantجاهل of such poverty-strickenمعدم subjects, and to study medicine he went. But his natural bent ميلshowed itself even here. For praying one day in theCathedralالكاتدرائية , like a good Catholic as he was all his life, his attention was arrestedلُفت إنتباهه by the great lampمصباح which, after lighting it, the vergerالشماس had left swingingمتأرجح to and froذهاباً وإياباً . Galileo proceededتابع to time its swings by the only watch he possessed إمتلك - viz., his own pulseنبض . He noticed that the time of swing remained, as near as he could tell, the same, notwithstandingعلى الرغم من the fact that the swings were getting smaller and smaller. By subsequent experiment he verified the law, and the isochronism of the pendulumالبندول was discovered. An immenselyبضخامة important practicalتطبيقى discovery this, for upon it all modern clocks are based; and Huyghens soon applied it to the astronomicalفلكى clock, which up to that time had been a crudeخشن and quite untrustworthy لا يستحق الثقة به instrument.
The best clock which Tycho Brahe could get for his observatoryمرصد was Inferiorذو نوعية أقل to one that may now be purchased for a few shillingsقليل من الشلنات and this change is owing to the discovery of the pendulum by Galileo. Not that he applied it to clocks; he was not thinking of astronomy, he was thinking of medicine, and wanted to count people's pulses. The pendulum served; and "pulsilogies," as they were called, were thus introduced to and used by medical practitioners. The Tuscan court came to Pisa for the summer months - for it was then a seaside place - and among the suite was Ostillio Ricci, a distinguishedمشهور
mathematician and old friend of the Galileo family. The youth visited him,and one day, it is said, heard a lesson in Euclid being given by Ricci to the pages while he stood outside the door entrancedمدخل . Anyhowعلى أى حال , he imploredيتوسل إلى Ricci to help him into some knowledge of mathematics, and the old man willingly consentedوافق – قبل . So he mastered Euclid, and passed on to Archimedes, for whom he acquiredمكتسب a great veneration,توقير. His father soon heard of this obnoxiousعرضة لكل ما هو بغيض proclivityميل , and did what he could to divertيحول him back to medicine again. But it was no use. Underneathتحت his Galenفتاة and Hippocrates were secreted copies of Euclid and Archimedes, to be studied at every available opportunity. Old Vincenzo perceivedلاحظ the bent of genius to be too strong for him, and at last gave way. With prodigiousإستثنائى rapidity سرعةthe released philosopher now assimilatedإستوعب the elements of mathematics and physics, and at twenty-six we find him appointed يوظف for three years to the university chair of mathematics, and enjoying the paternallyأبوى dreaded stipend of seven and a half pence a day.
Now it was that he ponderedتأمل over the laws of falling bodies. He verified, by experimentخبرة , the fact that the velocityسرعة acquired by falling down any slopeإنحدار of given height was independent of the angle of slope. Also, that the height fallen through was proportionalنسبى to the square of the time. Another thing he found experimentally was that all bodies, heavy and light, fell at the same rate, striking the ground at the same time. Now this was clean contraryبعكس to what he had been taught. The physics of those days were a simple reproductionتوالد of statements in old books. Aristotle had assertedأكد
certain things to be true, and these were universally عموماbelieved. No one thought of trying the thing to see if it really were so. The idea of making an experiment would have savoredتذوق of impiety,عدم التقوى because it seemed to tend يتجه إلى toward scepticismالشك , and cast a doubt on a reverendموقر authority. Young Galileo, with all the energy and imprudenceطيش of youth - what a blessing that youth has a little imprudence and disregardإهمال of consequences in pursuingمتابعة a high ideal! - as soon as he perceivedأدرك that his instructorsمعلم were wrong on the subject of falling bodies, instantlyبسرعة informed them of the fact. Whether he expected them to be pleased or not is a question. Anyhow, they
were not pleased, but were much annoyedمتضايق by his impertinent,وقاحة arroganceمتعجرف .
It is, perhaps, difficult for us now to appreciateيعجب preciselyبدقة their position. These doctrinesتعاليم دينية of antiquityعصور قديمة , which had come down hoaryقديم with age,
and the discovery of which had reawakened يعيد إيقاظ learning and quickenedيستعجل intellectualفكرى life, were accepted less as a science or a philosophy than as a religion. Had
they regarded إحترم Aristotle as a verballyلفظى inspiredملهم writer, they could not have
received his statements with more unhesitatingبلا تردد conviction.اقتناع In any disputeجدال as
to a question of fact, such as the one before us concerningاهتمام the laws of falling bodies, their method was not to make an experiment, but to turn over the pages of Aristotle; and he who could quote chapter and verseبيت شعرى of this great writer was heldيقتنى to settle the question and raise it above the reach of controversyجدال . It is very necessary for us to realize this state of things clearly, because otherwiseخلافا لذلك the attitude of the learned of those days toward every new discovery seems stupidأحمق and almost insaneمخبول . They had a crystallizedبلور system of truth, perfect, symmetricalتناسق ; it wanted no novelty, no additions; every addition or growth was an imperfectionنقص , an excrescenceزيادة , a deformityتشوه . Progress was unnecessary and undesired. The Church had a rigidقاسى system of dogmaعقيدة which must be accepted in its entiretyكل on pain of being treated as a hereticمنشق عن العقيدة .Philosophers had a cast-iron system of truth to match - a system founded upon Aristotle - and so interwovenيمزج with the great theological dogmasالعقائد اللاهوتية that to question one was almost equivalentمكافىء to casting doubt upon the other. In such an atmosphere true science was impossible. The life-bloodحياة of science is growth, expansion, freedom, development. Before it could appear it must throw off these old shacklesقيود of centuries. It must burst its old skin, and emergeيظهر للعيان , worn with the struggle, weakly and unprotected, but free and able to grow and to expand. The conflict was inevitableمحتم , and it was severeصارم . Is it over yet? I fear not quite, though so nearly as to disturbيزعج science hardly at all. Then it was different: it was terribleفظيع . Honor to the men who bore the first shock of the battle! معركة Now, Aristotle had said that bodies fell at rates depending on their weight. A five-pound weight would fall five times as quick as a one pound weight; a fifty-pound weight fifty times as quick, and so on. Why he said so nobody knows. He cannot have tried. He was not above trying experiments, like his smaller disciplesالتابعين ; but probably it never occurred to him to doubt the fact. It seems so natural that a heavy body should fall quicker than a light one; and perhaps he thought of a stone and a featherريش, and was satisfied. Galileo, however, asserted أكد that the weight did not matter a bitجزء; that
everything fell at the same rateدرجة - even a stone and a feather, but for the resistance of the air - and would reach the ground in the same time. And he was not content to be pooh-poohed and snubbed. He knew he was right, and he was determined مصمم to make everyone see the facts as he saw them. So one morning, before the assembledيجمع university, he ascendedصعد the famous leaning tower, taking with him a one-hundred-pound shot and a one-pound shot. He balanced وازن them on the edge of the tower, and let them drop together. Together they fell, and together they struckقرع the ground. The simultaneousمتزامن clangالطنين of those two weights sounded the death-knell of the old system of philosophy, and heralded the birth of the new. But was the change sudden? Were his opponents convinced? Not a jot. Though they had seen with their eyes and heard with their ears, the full light of heaven shining upon them, they went back mutteringهمهمة and discontentedمنكسر – خائب الأمل to their mustyمتعفن old volumes and their garrets, there to invent occult reasons for denying the validityصحة of the observation, and for referring it to some unknown disturbing cause. They saw that if they gave way on this one point they would be lettingترك go their anchorageرسو , and henceforward من الآن فصاعداwould be liable to drift along with the tide, not knowing whither. They dared not do this. No; they must cling to
the old traditions; they could not cast away their rotting ropes and sail out
on to the free ocean of God's truth in a spirit of fearlessشجاع faith. Yet they had received a shock: as by a breath of fresh salt breeze and a dash of spray in their faces, they had been awakened out of their comfortable lethargyالنعاس . They felt the approachالإقتراب of a new era. Yes, it was a shock, and they hated the young Galileo for giving it them - hated him with the sullen hatred of men who fight for a lost and dying cause. We need scarcely blame these men; at least we need not blame them overmuchبإفراط . To say that they acted as they did is to say that they were human, were narrow-minded, and were the apostlesهامش of a lost cause. But they could not know this; they had no experience of the past to guide them; the conditions under which they found themselves were novel, and had to be met for the first
time. Conductيوصل which was excusableيمكن إغتفاره then would be unpardonable now, in the
light of all this experience to guide us. Are there any now who practically
repeat their error, and resist new truth? who cling to any old anchorage of
dogma, and refuse to rise with the tide of advancing knowledge? There may be
some even now. Well, the unpopularity of Galileo smoulderedنار بدون لهب for a time, until, by another noble imprudence, he managed to offendيؤذى a semiroyalملكى personage, Giovanni de' Medici, by giving his real opinion, when consulted, about a machine which
De' Medici had invented for cleaning out the harbor of Leghorn. He said it was as useless as it in fact turned out to be. Through the influence of the mortified inventor he lost favor at court; and his enemies took advantage of the fact to render his chair untenable. He resignedإستقال before his three years were up, and retired to Florence. His father at this time died, and the family were left in narrow Circumstancesظروف . He had a brother and three sisters to provide for. He was offered a professorshipالأستاذية at Padua for six years by the Senate of Venice, and willinglyإرادى accepted it. Now began a very successful career. His introductory address was marked by brilliant eloquence, and his lecturesمحاضرات soon acquired fame.شهرة He wrote for his pupils on the laws of motion, on fortifications, on sun-dials, on mechanics, and on the celestial globe: some of these papers are now lost, others have been printed during the present century. Kepler sent him a copy of his new book, , and Galileo, in thanking him for it, writes him the following letter: " I count myself happy, in the search after truth, to have so great an ally as yourself, and one who is so great a friend of the truth itself. It is really pitiful that there are so few who seek truth, and who do not pursue a perverse method of philosophizingيفكر بطريقة الفلاسفة . But this is not the place to mourn over
the miseries of our times, but to congratulate you on your splendid discoveries in confirmation of truth. I shall read your book to the end, sure of finding much that is excellent in it. I shall do so with the more pleasure, because I have been for many years an adherent موالى of the Copernican system, and it explains to me the causes of many of the appearances of nature which are quite unintelligible on the commonly accepted hypothesis. I have collected many arguments for the purpose of refuting the latter; but I do not
venture to bring them to the light of publicity, for fear of sharing the fate
of our master, Copernicus, who, although he has earned immortal fame with
some, yet with very many (so great is the number of fools) has become an
object of ridicule and scorn. I should certainly venture to publish my
speculations if there were more people like you. But this not being the case,
I refrain from such an undertaking." Kepler urged him to publish his arguments in favor of the Copernican theory, but he hesitated for the present, knowing that his declaration would
be received with ridicule and opposition, and thinking it wiser to get rather more firmly seated in his chair before encountering the storm of controversy. The six years passed away, and the Venetian Senate, anxious not to lose so
bright an ornament, renewed his appointment for another six years at a largely
increased salary. Soon after this appeared a new star - the stella nova of 1604 - not the
one Tycho had seen - that was in 1572 - but the same that Kepler was so much
interested in. Galileo gave a course of three lectures upon it to a great audience. At the first the theatre was overcrowded, so he had to adjourn to a hall holding one thousand persons. At the next he had to lecture in the open air. He took occasion to rebuke his hearers for thronging to hear about an ephemeral novelty, while for the much more wonderful and important truths about the permanent stars and facts of nature they had but deaf ears.
But the main point he brought out concerning the new star was that it upset the received Aristotelian doctrine of the immutability of the heavens. According to that doctrine the heavens were unchangeable, perfect, subject neither to growth not to decay. Here was a body, not a meteor but a realdistant star, which had not been visible and which would shortly fade away again, but which meanwhile was brighter than Jupiter. The staff of petrified professorial wisdom were annoyed at the appearance of the star, still more at Galileo's calling public attention to it; and controversy began at Padua. However, he accepted it, and now boldly threw down the gauntlet in favor of the Copernican theory, utterly repudiating the
old Ptolemaic system, which up to that time he had taught in the schools according to established custom. The earth no longer the only world to which all else in the firmament
were obsequious attendants, but a mere insignificant speck among the host of heaven! Man no longer the centre and cynosure of creation, but, as it were, an insect crawling on the surface of this little speck! All this not set down in crabbed Latin in dry folios for a few learned monks, as in Copernicus' time, but promulgated and argued in rich Italian, illustrated by analogy, by
experiment, and with cultured wit; taught not to a few scholars here and there
in musty libraries, but proclaimed in the vernacular to the whole populace
with all the energy and enthusiasm of a recent convert and a master of
language! Had a bombshell been exploded among the fossilized professors it
had been less disturbing.
But there was worse in store for them. A Dutch optician, Hans Lippershey
by name, of Middleburg, had in his shop a curious toy, rigged up, it is said,
by an apprentice, and made out of a couple of spectacle lenses, whereby, if
one looked through it, the weather-cock of a neighboring church spire was seen
nearer and upside down. The tale goes that the Marquis Spinola, happening to
call at the shop, was struck with the toy and bought it. He showed it to
Prince Maurice of Nassau, who thought of using it for military reconnoitring.
All this is trivial. What is important is that some faint and inaccurate echo
of this news found its way to Padua and into the ears of Galileo.
The seed fell on good soil. All that night he sat up and pondered. He
knew about lenses and magnifying-glasses. He had read Kepler's theory of the
eye, and had himself lectured on optics. Could he not hit on the device and
make an instrument capable of bringing the heavenly bodies nearer? Who knew
what marvels he might not so perceive! By morning he had some schemes ready
to try, and one of them was successful. Singularly enough it was not the same
plan as the Dutch optician's: it was another mode of achieving the same end.
He took an old small organ-pipe, jammed a suitably chosen spectacle glass into
either end, one convex, the other concave, and, behold! he had the half of a
wretchedly bad opera-glass capable of magnifying three times. It was better
than the Dutchman's, however: it did not invert.
Such a thing as Galileo made may now be bought at a toy-shop for I
suppose half a crown, and yet what a potentiality lay in that "glazed optic
tube," as Milton called it. Away he went with it to Venice and showed it to
the Seigniory, to their great astonishment. "Many noblemen and senators,"
says Galileo, "though of advanced age, mounted to the top of one of the
highest towers to watch the ships, which were visible through my glass two
hours before they were seen entering the harbor, for it makes a thing fifty
miles off as near and clear as if it were only five." Among the people, too,
the instrument excited the greatest astonishment and interest, so that he was
nearly mobbed. The Senate hinted to him that a present of the instrument
would not be unacceptable, so Galileo took the hint and made another for them.
They immediately doubled his salary at Padua, making it one thousand florins,
and confirmed him in the enjoyment of it for life.
He now eagerly began the construction of a larger and better instrument.
Grinding the lenses with his own hands with consummate skill, he succeeded in
making a telescope magnifying thirty times. Thus equipped he was ready to
begin a survey of the heavens. The first object he carefully examined was
naturally the moon. He found there everything at first sight very like the
earth, mountains and valleys, craters and plains, rocks, and apparently seas.
You may imagine the hostility excited among the Aristotelian philosophers,
especially, no doubt, those he had left behind at Pisa, on the ground of his
spoiling the pure, smooth, crystalline, celestial face of the moon as they had
thought it, and making it harsh and rugged, and like so vile and ignoble a
body as the earth.
He went further, however, into heterodoxy than this: he not only made the
moon like the earth, but he made the earth shine like the moon. The
visibility of "the old moon in the new moon's arms" he explained by
earth-shine. Leonardo had given the same explanation a century before. Now,
one of the many stock arguments against Copernican theory of the earth being a
planet like the rest was that the earth was dull and dark and did not shine.
Galileo argued that it shone just as much as the moon does, and in fact rather
more - especially if it be covered with clouds. One reason of the peculiar
brilliancy of Venus is that she is a very cloudy planet. ^1 Seen from the moon
the earth would look exactly as the moon does to us, only a little brighter
and sixteen times as big - four times the diameter.
[Footnote 1: It is of course the "silver lining" of clouds that outside
observers see.
Wherever, Galileo turned his telescope new stars appeared. The Milky
Way, which had so puzzled the ancients, was found to be composed of stars.
Stars that appeared single to the eye were some of them found to be double;
and at intervals were found hazy nebulous wisps, some of which seemed to be
star clusters, while others seemed only a fleecy cloud.
Now we come to his most brilliant, at least his most sensational,
discovery. Examining Jupiter minutely on January 7, 1610, he noticed three
little stars near it, which he noted down as fixing its then position. On the
following night Jupiter had moved to the other side of the three stars. This
was natural enough, but was it moving the right way? On examination it
appeared not. Was it possible the tables were wrong? The next evening was
cloudy, and he had to curb his feverish impatience. On the 10th there were
only two, and those on the other side. On the 11th two again, but one bigger
than the other. On the 12th the three reappeared, and on the 13th there were
four. No more appeared. Jupiter, then, had moons like the earth - four of
them in fact! - and they revolved round him in periods which were soon
determined.
The news of the discovery soon spread and excited the greatest interest
and astonishment. Many of course refused to believe it. Some there were who,
having been shown them, refused to believe their eyes, and asserted that
although the telescope acted well enough for terrestrial objects, it was
altogether false and illusory when applied to the heavens. Others took the
safer ground of refusing to look through the glass. One of these who would
not look at the satellites happened to die soon afterward. "I hope," says
Galileo, "that he saw them on his way to heaven."
The way in which Kepler received the news is characteristic, though by
adding four to the supposed number of planets it might have seemed to upset
his notions about the five regular solids.
He says: "I was sitting idle at home thinking of you, most excellent
Galileo, and your letters, when the news was brought me of the discovery of
four planets by the help of the double eyeglass. Wachenfels stopped his
carriage at my door to tell me, when such a fit of wonder seized me at a
report which seemed so very absurd, and I was thrown into such agitation at
seeing an old dispute between us decided in this way, that between his joy, my
coloring, and the laughter of us both, confounded as we were by such a
novelty, we were hardly capable, he of speaking, or I of listening.
"On our separating, I immediately fell to thinking how there could be any
addition to the number of planets without overturning my Mysterium
Cosmographicon, published thirteen years ago, according to which Euclid's five
regular solids do not allow more than six planets round the sun. But I am so
far from disbelieving the existence of the four circumjovial planets that I
long for a telescope to anticipate you if possible in discovering two round
Mars - as the proportion seems to me to require - six or eight round Saturn,
and one each round Mercury and Venus."
As an illustration of the opposite school I will take the following
extract from Francesco Sizzi, a Florentine astronomer, who argues against the
discovery thus:
"There are seven windows in the head - two nostrils, two eyes, two ears,
and a mouth; so in the heavens there are two favorable stars, two
unpropitious, two luminaries, and Mercury alone undecided and indifferent.
From which and many other similar phenomena of nature, such as the seven
metals, etc., which it were tedious to enumerate, we gather that the number of
planets is necessarily seven.
"Moreover, the satellites are invisible to the naked eye, and therefore
can have no influence on the earth, and therefore would be useless, and
therefore do not exist.
"Besides, the Jews and other ancient nations as well as modern Europeans
have adopted the division of the week into seven days, and have named them
from the seven planets: now if we increase the number of the planets this
whole system falls to the ground."
To these arguments Galileo replied that whatever their force might be as
a reason for believing beforehand that no more than seven planets would be
discovered, they hardly seemed of sufficient weight to destroy the new ones
when actually seen. Writing to Kepler at this time, Galileo ejaculates:
"Oh, my dear Kepler, how I wish that we could have one hearty laugh
together! Here, at Padua, is the principal professor of philosophy whom I
have repeatedly and urgently requested to look at the moon and planets through
my glass, which he pertinaciously refuses to do. Why are you not here? What
shouts of laughter we should have at this glorious folly! And to hear the
professor of philosophy at Pisa laboring before the Grand Duke with logical
arguments, as if with magical incantations, to charm the new planets out of
the sky."
A young German protege of Kepler, Martin Horkey, was travelling in Italy,
and meeting Galileo at Bologna was favored with a view through his telescope.
But supposing that Kepler must necessarily be jealous of such great
discoveries, and thinking to please him, he writes: "I cannot tell what to
think about these observations. They are stupendous, they are wonderful, but
whether they are true or false I cannot tell." He concludes, "I will never
concede his four new planets to that Italian from Padua, though I die for it."
So he published a pamphlet asserting that reflected rays and optical illusions
were the sole cause of the appearance, and that the only use of the imaginary
planets was to gratify Galileo's thirst for gold and notoriety.
When after this performance he paid a visit to his old instructor Kepler
he got a reception which astonished him. However, he pleaded so hard to be
forgiven that Kepler restored him to partial favor, on this condition, that he
was to look again at the satellites, and this time to see them and own that
they were there.
By degrees the enemies of Galileo were compelled to confess to the truth
of the discovery, and the next step was to outdo him. Scheiner counted five,
Rheiter nine, and others went as high as twelve. Some of these were
imaginary, some were fixed stars, and four satellites only are known to this
day Footnote 1: A fifth satellite of Jupiter has been recently discovered; and
Kepler's guess at two moons for Mars has also been justified.
Here, close to the summit of his greatness, we must leave him for a time.
A few steps more and he will be on the brow of the hill; a short piece of
table-land, and then the descent begins.
In dealing with these historic events will you allow me to repudiate once
for all the slightest sectarian bias or meaning? I have nothing to do with
Catholic or Protestant as such. I have nothing to do with the Church of Rome
as such. I am dealing with the history of science. But historically at one
period science and the Church came into conflict. It was not specially one
church rather than another - it was the Church in general, the only one that
then existed in those countries. Historically, I say, they came into
conflict, and historically the Church was the conqueror. It got its way; and
science, in the persons of Bruno, Galileo, and several others, was vanquished.
Such being the facts, there is no help but to mention them in dealing with the
history of science. Doubtless now the Church regards it as an unhappy
victory, and gladly would ignore this painful struggle. This, however, is
impossible. With their creed the churchmen of that day could act in no other
way. They were bound to prosecute heresy, and they were bound to conquer in
the struggle or be themselves shattered.
But let me insist on the fact that no one accuses the ecclesiastical
courts of crime or evil motives. They attacked heresy after their manner, as
the civil courts attacked witchcraft after their manner. Both erred
grievously, but both acted with the best intentions.
We must remember, moreover, that his doctrines were scientifically
heterodox, and the university professors of that day were probably quite as
ready so condemn them as the Church was. To realize the position we must
think of some subjects which to-day are scientifically heterodox, and of the
customary attitude adopted toward them by persons of widely differing creeds.
If it be contended now, as it is, that the ecclesiastics treated Galileo
well, I admit it freely: they treated him as well as they possibly could. They
overcame him, and he recanted; but if he had not recanted, if he had persisted
in his heresy, they would - well, they would still have treated his soul well,
but they would have set fire to his body. Their mistake consisted not in
cruelty, but in supposing themselves the arbiters of eternal truth; and by no
amount of slurring and glossing over facts can they evade the responsibility
assumed by them on account of this mistaken attitude.
We left Galileo standing at his telescope and beginning his survey of the
heavens. We followed him indeed through a few of his first great discoveries
- the discovery of the mountains and other variety of surface in the moon, of
the nebulae and a multitude of faint stars, and lastly of the four satellites
of Jupiter.
This latter discovery made an immense sensation, and contributed its
share to his removal from Padua, which quickly followed it. Before the end of
the year 1610 Galileo had made another discovery - this time on Saturn. But to
guard against the host of plagiarists and impostors he published it in the
form of an anagram, which, at the request of the Emperor Rudolph - a request
probably inspired by Kepler - he interpreted; it ran thus: The farthest planet
is triple.
Very soon after he found that Venus was changing from a full-moon to a
half-moon appearance. He announced this also by an anagram, and waited till
it should become a crescent, which it did. This was a dreadful blow to the
anti-Copernicans, for it removed the last lingering difficulty to the
reception of the Copernican doctrine. Copernicus had predicted, indeed, a
hundred years before, that, if ever our powers of sight were sufficiently
enhanced, Venus and Mercury would be seen to have phases like the moon. And
now Galileo with his telescope verifies the prediction to the letter.
Here was a triumph for the grand old monk, and a bitter morsel for his
opponents.
Castelli writes, "This must now convince the most obstinate." But
Galileo, with more experience, replies: "You almost make me laugh by saying
that these clear observations are sufficient to convince the most obstinate;
it seems you have yet to learn that long ago the observations were enough to
convince those who are capable of reasoning and those who wish to learn the
truth; but that to convince the obstinate and those who care for nothing
beyond the vain applause of the senseless vulgar, not even the testimony of
the stars would suffice, were they to descend on earth to speak for
themselves. Let us, then, endeavor to procure some knowledge for ourselves,
and rest contended with this sole satisfaction; but of advancing in popular
opinion, or of gaining the assent of the book-philosophers, let us abandon
both the hope and the desire."
What a year's work it had been! In twelve months observational astronomy
had made such a bound as it has never made before or since ^1. Why did not
others made any of these observations? Because no one could make telescopes
like Galileo. He gathered pupils round him, however, and taught them how to
work the lenses, so that gradually these instruments penetrated Europe, and
astronomers everywhere verified his splendid discoveries.
Foot note 1: The next year Galileo discovered also the spots upon the sun and
estimated roughly its time of rotation.
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السبت يناير 11, 2014 11:34 pm