Recovered Writing: Undergraduate Age of Scientific Discovery, Copernicus and Galileo Essay, March 19, 2002

This is the twenty-third post in a series that I call, “Recovered Writing.” I am going through my personal archive of undergraduate and graduate school writing, recovering those essays I consider interesting but that I am unlikely to revise for traditional publication, and posting those essays as-is on my blog in the hope of engaging others with these ideas that played a formative role in my development as a scholar and teacher. Because this and the other essays in the Recovered Writing series are posted as-is and edited only for web-readability, I hope that readers will accept them for what they are–undergraduate and graduate school essays conveying varying degrees of argumentation, rigor, idea development, and research. Furthermore, I dislike the idea of these essays languishing in a digital tomb, so I offer them here to excite your curiosity and encourage your conversation.

I wrote this essay for Professor Robert Wood’s LCC 2104 Age of Scientific Discovery class at Georgia Tech. This was shortly after I was readmitted to the program after working in IT for several years. My citations are sloppy and incomplete and the writing is evidence of my writing’s early stages and on-going development. This is the second of three essays from Professor Wood’s class.

Jason W. Ellis

Professor Robert Wood

LCC 2104 Age of Discovery

March 19, 2002

Essay 2

Copernicus and Galileo both had unique scientific methodologies that they applied to their work in astronomy. Copernicus shows a reliance on that of the past and he builds on the work of others. He is not merely making commentary, but transposing his own findings on that which came before. Galileo takes this a step further by understanding what has been said and relying on his observational work to be the interpretation of the heavens. He also extends his work into the world through letters and publishings to open discourse between himself and others. Thus creating a dynamic to possibly find faults in his findings or show fault in the findings of others.

The beginning of the revolution concerning understanding how the planets of our solar system are arranged started with the work of Copernicus with the work De revolutionibus. Copernicus conducts his observations and mathematical deductions on the precept in Hallyn that, “as the beneficiary for whom the world was made, man can attain true knowledge. In place of a universe whose beauty and rationality escape us, and which thereby calls us to humility, Copernicus substitutes a cosmos for which man is the final purpose and whose true plane he can reconstruct.” Additionally, Hallyn writes, “Copernicus was not content to admire an inaccessible wisdom “from afar”; he believed that science must permit man to penetrate the arcana of the divine plan and must be willing to submit to complete reform if necessary to achieve this anagogical goal.” Copernicus elevates the status of man and astronomer to one who is able to spy the truth in nature through observation and deductions based on those observations.

Work done by predecessors and particularly, the ancients, Copernicus valued a great deal. He viewed astronomy as building on itself with the work done by those who came before. In Hallyn, there is this passage and quote of Copernicus regarding acknowledging the prior works of others.

Copernicus takes care, moreover, to emphasize that the very theory he is proposing is based on an ancient hypothesis concerning the nature of the universe:

I undertook the task of rereading the works of all the philosophers which I could obtain to learn whether anyone had every proposed other motions of the universe’s spheres than those expounded by the teachers of astronomy in the schools. And in fact first I found in Cicero that Nicetas supposed the earth to move. Later I also discovered in Plutarch that certain others were of this opinion…Therefore, having obtained the opportunity from these sources, I too bean to consider the mobility of the earth. And even though the idea seemed absurd, nevertheless I knew that others before me had been granted the freedom to imagine any circles whatever for the purpose of explaining the heavenly phenomena. Hence I thought that I too would be readily permitted to ascertain whether explanations sounder than those of my predecessors could be found for the revolution of the celestial spheres on the assumption of some motion of the earth.

Hallyn writes, “the importance of this passage lies not only in the way it recalls certain precursors, but also in the weight it ascribes to a particular form of renovatio based on the liberty to think, which may in turn lead to innovatio.” Copernicus is learning about ideas that surfaced in the past. Some of those ideas might not have been popular or they might not have had the ability to prove them properly at that time. Now he decides to take some of these ideas and try them on his own. He makes them his hypotheses which he will test with observation and he will apply his knowledge of mathematics to what he finds. He understands that the technology and mathematics of his time in regard to astronomy is greater than that which they had in previous times. This affords him a certain ability to learn new truths and a liberty to investigate further than those before him. Thus the “renovatio,” the renovation of ideas leads to “innovatio,” innovation born of those ideas.

His work in De revolutionibus is analogous to his search for truth. It is a transformation of old ideas into the next level. He is not merely commenting on previous work, but he is taking what he has learned from others, particularly, Ptolemy, and from his mathematical treatments on that work to develop the next plateau of understanding. Debus writes, “in short, the Ptolemaic system was recast.” The sun was placed at the mathematical center of the universe. This was surrounded by the planets, each set in their crystalline spheres. Outside this was the sphere of fixed stars. The Copernican system retained a good deal of complexity found in the Ptolemaic system, but he had simplified some things. Copernicus had eliminated equant circles and epicycles that explained retrograde motion were almost completely resolved (if he had accepted elipical orbits this would have been fully resolved). Additionally his system allowed for relative distances of the planets from the sun to be calculated using trigonometry.

It cannot be too lightly stressed that Copernicus has a great respect and reliance on Ptolemy. Copernicus even notes concern regarding his belief in the basis of the Ptolemic system when he says in Hallyn, “not to disorient the diligent reader by straying too far from Ptolemy.” He takes Ptolemy’s work, internalizes it and then rebuilds it with the additional information and knowledge that he has. For Copernicus astronomy is an interpretive and transformative process. It is interpretive because new ways of explaining data may be found. it is transformative because an earlier concept or work is elaborated on and changed into a new system based on the old.

The methodology used by Galileo is slightly different than that used by Copernicus. Galileo relies on a system closer to that which we see today in the sciences. The telescope is better refined and it’s power much better than that used by Copernicus. Thus Galileo uses this for more accurate observations. Also he relies on diligent and regular observational data. One cannot observe occasionally and expect to get data that show trends or behavior over time accurately. Building on this concept he puts forth the idea that if someone follows his procedures for observation, using a similar apparatus, the observation can be reproducible from different locations. This means someone in Rome can make the same observation of sun spots that someone in Florence can make.

Standards in observation were something he adherently held to in order to build data that can be accurately interpreted and used by different persons. In his observations on sunspots Galileo notes how he makes these observations so that they are accurate. On pages 115-116 of Drake, Galileo notes the method he uses that was developed by his pupil Benedetto Castelli. His description is very precise and descriptive. If someone wanted to begin observing sunspots they could easily use this method that Galileo describes to do so.

The structure of the “Letters on Sunspots” in Discoveries and Opinions of Galileo also serve to show the desire Galileo had for discourse in the science of astronomy. He believed that a well reasoned argument with supporting evidence should sway any dissenting voice to the truth of his argument. The “Letters on Sunspots” show him answering, by way of letter, questions and counter-arguments from his dissenters. He is exact in explaining his point of view and he follows up by pointing out how the argument from a dissenter might be mistaken or incorrect. During this time the Aristotelians still were a dominant force in the academia. An important point that Galileo makes is that even Aristotle would arrive at similar conclusions as himself if he had had the apparatus that was available during Galileo’s time.

Galileo differs from Copernicus in that instead of relying and giving a great deal of credit to the work done before him, he relies much more heavily on the accumulation of observational data and of reasoning through that data. Through Galileo’s work he was able to prove that the Copernican system was essentially true.

One of the most important distinctions that Galileo presses is that of naming. Prior to and during Galileo’s time, many astronomers would refer to objects or lights in the heavens as “stars.” Planets, supernovae, comets, and everything else were grouped together in this manner and referred to as “stars.” When you are attempting to explain something and how it is different from something else, nomenclature is very important. In his work, “The Starry Messenger,” Galileo goes to great lengths to describe and illustrate the differences between things in the heavens. This is necessary for him to describe the moons of Jupiter, or as he called them, the Medicean planets. In his illustrations on pages 52-65 of Drake, he not only shows regular depictions of the location of the Medicean planets, but also their relative size or brightness. Through the course of the illustrations one can see the nature of rotation they make around Jupiter.

Galileo and Copernicus each have a particular way about which they discovered truth about the way in which the solar system operates. Copernicus built on the knowledge of others augmenting and modifying that with his own intuition, observation, and mathematical ability. Galileo took this a step farther by incorporating a more detached view of the heavens by relying on observational data to prove his points. The methods of Galileo show a strong resemblance to that of scientific observation today: observation, deduction, reporting, peer review and discussion.



Works Cited


Debus, Allen G. Man and Nature in the Renaissance. New York, New York: Cambridge University Press, 1978.


Drake, Stillman, ed. Discoveries and Opinions of Galileo. Trans. Stillman Drake. New York, New York: Anchor Books, 1957.


Hallyn, Fernand. The Poetic Structure of the World: Copernicus and Kepler. Trans. Donald M. Leslie. New York, New York: Zone Books, 1987.


Published by Jason W. Ellis

I am an Associate Professor of English at the New York City College of Technology, CUNY whose teaching includes composition and technical communication, and research focuses on science fiction, neuroscience, and digital technology. Also, I direct the B.S. in Professional and Technical Writing Program and coordinate the City Tech Science Fiction Collection, which holds more than 600 linear feet of magazines, anthologies, novels, and research publications.