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GALILEO AND HIS JUDGES.
GALILEO AND HIS JUDGES
BY
F. R. WEGG-PROSSER.
LONDON: CHAPMAN AND HALL,
LIMITED.
1889.
[_All rights reserved._]
CHARLES DICKENS AND EVANS,
CRYSTAL PALACE PRESS.
PREFACE.
There is no name in the annals of science which has been the occasion
of so long and fierce a controversy as that of Galileo. The historian,
the astronomer, and the theologian have all had a share in it.
Sometimes there has been a pause in the strife, and the question has
been allowed to rest; but after a while another disputant has rekindled
the embers, and the struggle has recommenced. This has been the case
within the last few years, some writers of considerable ability having
appealed to the history of Galileo in order to give point to opinions
that they wished to advance. During all this time, if there has been
unfairness on one side, there have been injudicious zeal and inaccuracy
on the other.
These circumstances must form my apology for interfering in a dispute
already so prolonged and so envenomed; and it has appeared to me that I
may without presumption hope to amend the errors to which I have just
alluded, if in no other way, at least by stating correctly the facts
of the case. I do not, however, undertake to write a full biography of
the great philosopher, or to give a detailed account of his numerous
contributions to the scientific literature of his day; I confine myself
principally to those great crises in his life which have given rise to
so much discussion, and which have chiefly contributed to make him a
name in history.
CONTENTS
Preface v
Chapter I 1
Chapter II 13
Chapter III 42
Chapter IV 78
Chapter V 136
GALILEO AND HIS JUDGES.
CHAPTER I.
Before entering on any details relating to Galileo’s life and works,
I propose to give a brief sketch of the progress of astronomical
knowledge up to his time; for without this, one cannot appreciate
correctly the value of his contributions to science, a value
exaggerated or underrated by different writers, each according to his
respective bias.
The primitive conception of the Earth as a vast plain with the ocean
flowing round it, and the solid firmament in the sky above it, with the
Sun, Moon, and Stars driven across by some mysterious agency, need not
be noticed from an astronomical point of view; it appeared naturally
in ancient poetry and in the forms of speech adopted and continued by
popular usage; but it is not necessary to dwell upon it.
The first astronomers with whom we are acquainted were the Greeks,
though it is said by some writers that the Chaldeans and Egyptians were
really the original astronomers of the ancient world, and what the
Greeks knew was borrowed from them.
The vast majority of men from the earliest times down to the birth of
Galileo believed that the Earth was the centre of the universe, round
which the Sun, Moon, and Stars revolved every twenty-four hours; round
which, also (as careful observers had perceived), the Sun had an annual
motion, progressing through the various signs of the zodiac; moreover,
it had been noticed that the planets moved round the Earth, though at
widely differing periods.
Yet there had been some few men, exceptionally gifted, who had guessed
(and truly so) that the popular conception was a wrong one. It is said
that the old Greek philosopher, Pythagoras, taught his disciples that
the Sun was the real centre of our system, and that the Earth and
planets circulated round it; but he does not seem to have openly and
explicitly published his doctrine, though the tradition of his having
so taught has always existed. If he taught it, however, he stands
almost alone among the ancients. There were two great authorities
in particular, whose opinion carried immense weight, and who were
both decided in holding that the Earth was the centre, and the Sun
a revolving planet. The first of these, Aristotle, has exercised an
influence over succeeding generations which is simply marvellous.
How vast was the weight of his name as a philosopher in the age of
the schoolmen is well known to every one who has ever glanced at the
greatest work of the greatest intellect of that age, the “Summa” of
St. Thomas Aquinas. This celebrated writer quotes him as “philosophus,”
in his opinion _the philosopher par excellence_, and besides his
general appreciation of him as thus shown, he wrote an elaborate
treatise on the “Astronomy” of Aristotle.
Nor has this influence been confined to the schoolmen; it has remained
ever since, even to this day and in this country, where in the
University of Oxford his great work on ethics is still a standard book
of study. At the time of Galileo, such was the reverence felt towards
his authority in Italy and in Rome, that the Peripatetici, as those
who specially belonged to his school were called, were probably quite
as indignant with the revolutionary astronomer for disregarding the
teaching of their philosopher, as for going counter to the literal
interpretation of Scripture.
But in pure astronomy, apart from all other philosophy, the greatest
of all ancient writers was Ptolemy, who in the second century of the
Christian era wrote a work called the “Almagest,” which is a complete
compendium of the science as known at that date. Ptolemy probably
borrowed very much from his great predecessor, Hipparchus, who has been
called the father of astronomy, and who was the first to discover--to
take a remarkable instance--the phenomenon known as the precession of
the equinoxes, involving as it does the difference in length between
the solar and sidereal years. The system of Ptolemy was briefly this:
The heavens and the Earth are both spherical in form--the Earth being
immovable in the centre, and all the heavenly motions taking place in
circles. For this he gives his reasons--sound and good reasons for the
spherical shape of the Earth; unsound and mistaken, however, for the
denial of the Earth’s rotation on its axis, an opinion he evidently
knew had been maintained by some persons; one important argument
on this latter head being that if the Earth rotated with the great
velocity necessary to carry it round in one day, it would leave the air
behind it. He places the Earth (as already said) in the centre, then
the Moon as the nearest planet revolving round it, the next Mercury,
then Venus, then the Sun, and beyond these Mars, Jupiter, and Saturn.
All moved in circles, but since, with the exception of the Sun and
Moon, simple circles would not account for the motions, he supposes
small circles in a retrograde direction forming loops upon the main
circle, which he calls _epicycles_; undoubtedly following in this
respect, Hipparchus, who three centuries before had struck out the
same idea. It is curious that Ptolemy’s arguments (as above mentioned)
show clearly that in his day there were some persons, though their
names have perished,[1] some one or two philosophers endowed with a
marvellous insight into Nature, who had guessed at the true solution
of the great astronomical problem; but they left no enduring mark on
their age. The system of Ptolemy accounted for all the phenomena of
the heavenly bodies that could be observed without the use of the
telescope; naturally it held undisputed sway for many generations.
The first writer who revived the doctrine of Pythagoras as to the
Earth’s movement (if, indeed, Pythagoras ever really taught it) was
Nicholas de Cusa; he was a German by birth, having, in fact, been born
at Trèves, in 1401; but he was educated in Italy. He rose to a high
ecclesiastical position, and was created cardinal by Pope Eugenius IV.,
in 1448; his book just alluded to was entitled “De Docta Ignorantia,”
and was dedicated to Cardinal Cesarini.
The first, however, whose work obtained any great notoriety, and
who upheld the doctrine that the Earth revolved around the Sun, was
Nicholas Kopernik, commonly called by the Latinised form of his name,
Copernicus. He, too, was a German, born at Thorn, in 1473; he studied
for a time at the University of Cracow, and like Nicholas de Cusa,
afterwards in Italy, and was subsequently raised to the ecclesiastical
dignity of a Canon. It is probable that he was not a priest (though he
is frequently spoken of as such), but a Canon in minor orders. In 1500
he was appointed professor of mathematics at Rome; and such was his
scientific reputation that he was consulted by the Council of Lateran,
held in 1512, on the question of the reform of the calendar--a reform
carried out at a later period by Pope Gregory XIII.
The system of Copernicus was well received at Rome. A German disciple
of his, John Albert Widmanstadt, in the year 1533, expounded it before
Pope Clement VII., and produced a very favourable impression. Nor was
the favour shown to Copernicus and his teaching ever withdrawn at Rome;
his great work, “De Revolutionibus Orbium Cœlestium” (published, it
is said, by the advice of Cardinal Schunberg, Bishop of Capua), was
dedicated to the reigning Pope, Paul III.; nor does he appear to have
received at any time the least rebuke or discouragement from the Holy
See; he died, however, immediately after the printing of his book, in
May, 1543.
Copernicus supposed the heavenly bodies, the Earth included, to revolve
round the Sun in _circles_; but, as it was evident that they did not
exactly do this, he used the theory of epicycles, and supposed each
planet to make two revolutions in each epicycle for every revolution
round the Sun. The true solution of the difficulty was due to Kepler,
who lived in the next century, and who discovered that the planets
moved in _ellipses_. Copernicus held, and, of course, held truly, that
the Earth revolves on its axis, thereby causing the apparent diurnal
motion of all the heavenly bodies from east to west.
Owing to his work having been the first of any great importance that
maintained argumentatively the system called _heliocentric_, that is
to say, in which the Sun is the real centre, round which the planets,
including the Earth, revolve--for the treatise of Nicholas de Cusa
does not appear to have had any extensive circulation--it is usual
to speak of this system as the _Copernican_ one, notwithstanding the
errors from which its great author was unable to extricate himself, and
which have long since been rectified by subsequent writers; so that
even at this day we retain the name.
It is always useful in scientific subjects to introduce a definition;
and this is my definition of the sense in which I employ the word
Copernican, that it is simply as opposed to the system in which the
Earth is the centre of the visible universe, and the Sun revolving
about it. It is, in fact, less accurate but more convenient than the
employment of the Greek words heliocentric and geocentric to denote
the two systems. Greek words, no doubt, abound in our scientific
vocabulary, as the following plainly show: astronomy, geology,
geography, barometer, thermometer, microscope, telescope; but these
have become naturalised in our language by long use, which heliocentric
and geocentric have not as yet been.
After Copernicus there arose an astronomer of great merit, a Dane,
Tycho Brahé by name, who attempted to start a fresh system--a
modification, in fact, of that of Ptolemy. He made all the planets
revolve round the Sun, and the Sun, accompanied by the planets, round
the Earth. He deserves great credit for his painstaking observations;
but he lived just before the invention of the telescope--or, at least,
before it was used for astronomical purposes--and, therefore, was
under an infinite disadvantage. His chief objection to the system of
Copernicus was one at which a modern astronomer would smile, but which
in those days seemed very weighty--namely, the enormous distance at
which you must suppose the fixed stars to be situated, if it were true.
The philosophers of that age did not like to admit such a waste of
space as that which must intervene between the orbit of Saturn and the
stars. And, on the Copernican theory, if the stars were not situated at
an immense, almost infinite distance, they ought to appear to move in
a way they certainly do not. Tycho Brahé was born in 1546. His theory
never made much way; it had not, I imagine, sufficient elements of
probability to recommend it generally; while the subsequent invention
of the telescope, and the works of Kepler and Galileo, coming so soon
after Tycho Brahé, prepared the way for that almost universal reception
of the Copernican system which we have since witnessed. I shall refer
later on to Tycho and his observations.
Such, then, was the state of astronomical theories in the latter
part of the sixteenth century. Enlightened men like Copernicus had
guessed--not accurately, it is true, but with a considerable approach
to accuracy--at the real facts of the case. Tycho Brahé (who, I
suspect, would have been converted to Copernicanism if his life had
been prolonged) had suggested a system of compromise not likely, in
the long run, to satisfy any thoughtful mind; while the bulk of men,
even the learned, adhered to the old Ptolemaic scheme. Something,
however, now occurred which was destined to work, sooner or later, a
complete revolution in astronomy. The telescope was invented, and, at
the same time, there arose a man who knew how to use it: that man was
Galileo. He was not the inventor of it, for it was first constructed
in Holland or Belgium; yet he had the energy and the skill to make a
telescope, without having previously seen one, simply from the account
he had heard of the instrument. The telescope that he constructed,
which still bears his name, was the simplest possible. It was of a
form now disused excepting for opera-glasses and for the far more
powerful binocular field-glasses with which we are so familiar; but for
telescopes properly so called an improved principle has long since been
introduced. Galileo was the first man that ever, so far as we know,
turned the telescope upon the heavens. How he was rewarded for his
pains we shall presently see; and I propose to introduce a narrative of
the principal events in his life, since there are no means for forming
a judgment so valuable as having the facts of the case clearly before
the mind.
For most of the facts I am indebted to M. Henri de l’Épinois, whose
elaborate article in the French publication known as _La Revue des
Questions Historiques_ is of the highest value; as the author of this
article has done what I suspect very few writers on Galileo have even
attempted to do, namely, to inspect the documents preserved in the
Vatican bearing on the process, some of which he gives at full length.
Not having myself had the same advantage, I yet feel that I am treading
on safe ground when I take my facts from M. de l’Épinois; for there
is scarcely a statement that he makes for which he does not give his
authority, whether from the documents just mentioned, or from Galileo’s
own letters, or from other trustworthy evidence.[2]
To treat of Galileo, and to pass over the events which brought him
into collision with the ecclesiastical authorities, would of course be
impossible, nor is it easy to touch upon these matters without having
some standpoint of one’s own--some principle to guide one, some basis
from which to argue. I do not shrink from stating that I write from a
Catholic standpoint; but without entering minutely into those subtle
questions which are the province of the trained theologian.
As, however, a good deal of the narrative is connected with the
action of the Roman Congregations, as they are termed, it may not be
superfluous to explain briefly the nature of these institutions. They
are formed by the selection of certain Cardinals, one of them acting as
Prefect of the Congregation, to whom are added other ecclesiastics as
consultors and as secretary. The Congregation of the Index, to which
reference will hereafter be made, was instituted not long after the
Council of Trent, by Pope St. Pius V., and has for its duty, as its
name implies, the pointing out to the faithful people such books as
they ought to abstain from reading. The chief consultor of the Index
is the “Master of the Apostolic Palace,” whom I shall have occasion
to mention more than once in connection with that Dialogue of Galileo
which brought him into such serious disgrace at Rome.
The Congregation of the Inquisition--I need hardly say, not to be
confounded with the Spanish tribunal of that name, which was founded at
an earlier period, nor with similar tribunals in other countries--was
erected in 1542 by Pope Paul III., and besides the other officials
attached to it, had certain theologians called “qualifiers,” whose duty
it was to give an opinion to the Congregation on questions submitted to
them.
These two Congregations, as well as several others which it is not
necessary to enumerate, still exist, their functions being somewhat
modified by the changing circumstances of the age. Their action is for
the most part confined to matters of discipline, but they sometimes
have questions of doctrine and moral obligation referred to them by the
Pope, from whom, of course, they derive all authority that they possess.
I do not here undertake to show the advantage and utility of these
Congregations, or of any other institutions connected with the
discipline of the Catholic Church. From the remarks I have just
previously made, it will be understood that I take all this for
granted, and that I feel justified in doing so. Those who differ from
me will, I trust, excuse me when they find that this conviction on my
part does not interfere with the impartial fairness of my narrative.
Galileo, whom I believe to have been a devout Catholic, would, if he
were here to speak for himself, agree with me in principle, however
he might complain of the action of the Roman Congregations in his own
individual case.
We shall then, as we proceed, inquire whether this celebrated
philosopher was, as some imagine, a hero and a martyr of science, or,
as others think, a rash innovator, who happened by chance to be right,
but who had little or nothing but vain and foolish arguments to adduce
in support of his doctrines. Perhaps we shall find that such critics,
on either side, are but imperfectly acquainted with the facts of the
case.