People's Democracy

(Weekly Organ of the Communist Party of India (Marxist)


No. 11

March 22, 2009


Galileo: Revolution Through The Telescope


Pure logical thinking cannot yield us any knowledge of the empirical world; all knowledge of reality starts from experience and ends in it. Propositions arrived at by purely logical means are completely empty as regards reality. Because Galileo saw this, and particularly because he drummed it into the scientific world, he is the father of modern physics -- indeed, of modern science altogether ---- Albert Einstein

THE International Astronomical Union and UNESCO have proposed that 2009 be celebrated as the International Year of Astronomy. The year marks the 400th anniversary of the first use of the telescope for astronomical observations by the Italian scientist Galileo Galilei in 1609. Galileo experimented with various combination of lenses and soon realized that the concave lens (eyepiece) should have more power compared with convex lens (objective) for good magnification. Since such combination of lenses were not available in the market he learnt the art of grinding lenses and within 3 months constructed a telescope of 30 fold magnification by 1610. In the hands of Galileo the telescope became a valuable tool. His observations were to provide evidence regarding the validity of the heliocentric theory proposed by Copernicus --- which proposed that the sun and not the earth was the centre of the solar system. The validation of this theory laid to rest the basic premise of the Aristotelian view of the universe, which held that the earth lay at the centre of the solar system. In many ways, Galileo’s work laid the foundation of modern Astronomy and in some ways of modern Physics.



The celebration of the International year of astronomy offers an opportunity to appreciate the path-breaking role played by Galileo. Galileo wrote a number of letters, pamphlets and books --all in Italian. This itself was a revolutionary act, for in those days all scholarly works were written in Latin. A Dialogue concerning two chief world systems and Discourses and Demonstrations Concerning Two New Sciences are two of his famous books. Galileo’s idea of formulating problems in a precise mathematical language and verifying theory by devising controlled experiments using specially constructed devices was a revolutionary contribution to the method of science. Galileo is, of course, widely known for his spirited defence of the heliocentric theory. His beliefs led to a trial by inquisition, after which he was sentenced to house arrest. In the process of defending the heliocentric theory Galileo raised an issue which was virtually taboo in his times --- the relationship between science and religion.

In the Aristotelian scheme the Universe was sought to be divided into two parts: the earth (known as the sub-lunar world) and heavenly bodies (the moon, sun, planets and stars). The important feature of Aristotle’s scheme is the geocentric theory. The earth is assumed to be the centre of the Universe and it is at rest. All the other heavenly objects move around the earth.

Christianity adopted Aristotle’s view of the universe, and we find numerous references to this model in religious texts. The scriptures clearly said that the earth lay at the centre of the Universe and it is at rest, while all the planets and the sun revolve around the earth. Christian theology viewed man (and so the earth) as imperfect and corruptible, which is consistent with the Aristotelian view that the heavenly objects were symbols of perfection and of incorruptible nature. The geocentric model of Aristotle was refined by Ptolemy, who offered detailed calculation to trace the movements of planets. Copernicus was not satisfied with Ptolemy’s model and he proposed heliocentric theory. His book De Revolutionibus Orbium Celestium was published in 1543, the year in which Copernicus died. Interestingly, the book was banned in 1616 when Galileo was facing his first Inquisition.

When Galileo turned the telescope towards the sky, it was as though a whole new hitherto unknown universe started unfolding. His first discovery was that the moon was mountainous --- he even estimated the height of the mountains. This was the first blow to the Aristotelian scheme, since it established that a “heavenly object” was in fact no different from the earth. He next discovered four moons orbiting around the planet Jupiter. This discovery also took away the special status of earth by showing that another planet had moons as well. He confirmed Copernicus’s hypothesis regarding phases on the planet Venus and also discovered the phenomenon of sunspots.

While these discoveries made Galileo immensely popular, they also led to him being treated with suspicion by his contemporaries. Some even rejected the idea that an object can be invisible to the naked eye but can be seen through a telescope and some believed these to be illusions created by the ghosts. Galileo was known to ruthlessly attack his opponents with wit and sarcasm. His opponents joined together to accuse him of heresy. Consequently, there were two inquisitions against him. The fist inquisition was conducted in1616 and the Vatican Church let him off with a warning not to uphold the Copernican theory. In 1632 he published his famous book The Dialogue Concerning Two Chief World Systems which was a defence of the Copernican theory. The book was written in the form of dialogues between three characters. One of these characters was called Simplico representing Aristotelian views. Simplico was made to look foolish and naïve. His opponents campaigned that that Simplico was a caricature of Pope himself. The second Inquisition tried him in public and he was first sentenced to imprisonment, but considering his age the sentence was restricted to house arrest. His book was banned and the ban was lifted only in 1835.



Galileo’s story is brings out in all its complexity, the relation and the contradiction between science and religion. Galileo’s forceful espousal of his ideas helped lay the foundation of science as an autonomous body of knowledge independent of religion. At that time theology was termed as Queen of Sciences, and philosophy was seen as being to theology. Interestingly, Galileo himself started off as a devout Christian, but his honest rendering of his discoveries drew him into a battle with the Church. Galileo was to quickly realise that there was indeed a contradiction between the heliocentric theory and the Bible. How does Galileo, still a staunch believer, resolve this contradiction? He does so by arriving at a compromise where he proposes that science and religion need to exist in different domains, and science cannot be subservient to religion. His main arguments were: a) the passages in the Bible should not be interpreted, literally, since they are written for the common man for the purpose of achieving salvation. The interpretations of the Bible are not unique, implying that that the Vatican Church’s interpretations are not final; b) In case there is a contradiction between science and the Bible, the conclusions from science should be trusted and the passages in the Bible have to be suitably reinterpreted so that the conclusions based on the science can be accepted as valid truth. In essence his arguments argue for a delinking of religion from the enterprise of understanding nature.

Galileo’s arguments, perhaps unwittingly, led him to the position of a materialist attempting to resolve the contradiction between science and religion. It is interesting to note that before the ascendancy of Christianity, science in Europe was not linked, inextricably, with religion. Bernard Pullman in History of Atoms writes about science in Greece as practiced around 600 BC: At a time when most people believed the observable world to be ruled by a plethora of gods with extraordinary powers but strangely human weakness and appetite, a handful of Hellenistic thinkers provide instead a rational explanation involving only natural causes and effects, without invoking transcendent powers. That is not to say they denied the existence of such powers, but they were determined not to get things mixed up.

In the medieval ages, for centuries, human enterprise aimed at understanding nature, became subservient to religion and lost its way. It goes to the credit of the likes of Galileo that science could be resurrected as an autonomous endeavour of understanding nature, unfettered by the shackles of religion. Einstein captures this role of Galileo as follows: A man is here revealed who possesses the passionate will, the intelligence, and the courage to stand up as the representative of rational thinking against the host of those who, relying on the ignorance of the people and the indolence of teachers in priest’s and scholar’s grab, maintain and defend their positions of authority. His unusual literary gift enables him to address the educated men of his age in such clear and impressive language as to overcome the anthropocentric and mythical thinking of his contemporaries and lead them to back to an objective and causal attitude toward cosmos, an attitude which had become lost to humanity with the decline of Greek culture.

Galileo’s life and message is relevant in today’s India, especially in the context of the politics of “Hindutva.” The stand of the votaries of Hindutva on Babri Masjid and the Sethusamudram canal project negates the very basis of science. In the affidavit submitted to the Supreme Court, the Archaeological Survey of India asserted that there is no evidence to prove that the Adam’s bridge is man-made: “The petitioners Subramaniam Swamy and others relied upon the contents of Valmiki Ramayana, Ramacharitmanas by Thulasidas and similar other texts….It is also submitted that the study of the human history, which is the primary object of the ASI, like other sciences and fields of study must be carried out in a scientific manner, using available technological aids and its findings must be based on tangible evidences.” Being a science based institution, ASI could not have supported the scriptures. Unfortunately, instead of accolades, they were rewarded with suspension!