Copernican Revolution


Copernican Revolution

 Edip Yuksel

The water was getting hotter and hotter.

Copernic, at a crucial moment, put the candle in the center, and it started boiling.

Copernican model can be considered the last push for the birth of famous twins: Renaissance and Reformation. Or, it can be illustrated as the last uppercut which knocks down the prehistoric monster, the Ptolemaic system. Or, it can be likened to a last candle in the right place that  boiled the water of scientific and social revolutions.

Several decades before Copernic’s birth until the declaration of Copernican system (1543) a great evolution was occurring in the history of Europe. All were adding more heat to the water.

With successful voyages men was learning that the ancient maps were full of errors. Consequently, those observations was braking the sacred spell of many ancient gods of geography and astronomy, such as Ptolemy. Luther and Calvin  were leading a revolt against the hegemony of Catholic church. Calendar was needed corrections, requiring an astronomical reform. Ptolemy’s original formulation was becoming inadequate. Numerous modified  models were replacing the original sacred Ptolemaic system. However, the discontent was increasing with each modification.

Furthermore, Humanist or Neoplatonist movement was shaking the Aristotalian concepts. Seeking simpler formulas to explain natural phenomena was becoming a scientific trend. The Ptolemaic planetary theory was being perceived too complex and cumbersome. The Humanist or Neoplatonist symbolism was falling in love with light and Sun. Sun was being praised as the lamp, the mind, and the Ruler of the universe.

Discontent and frustration with the Ptolemaic system, loosing faith in ancient philosophers, practical need for a better calendar, a new scientific attitude preferring qualitative neatness and simplicity, rebellion against the oppression of church, yes, all of these psychological and social factors created a militant intelligentsia and a scientific elite that was ready to put the sun in the center. Putting the sun in the center was similar to raise the flag of revolution. It was the first concrete monument that could express all of the feelings and information accumulated throughout the centuries.

Copernican system had some artistic advantages over the Ptolemaic system. Its superiority to Ptolemaic astronomy is obvious in many accounts:

  1. It, ultimately, did not need epicycles and eccentrics.
  2. It was suggesting a simpler and “more natural” model of the motions of inferior planets. As a uniform system, it did not need extra assumptions to determine both the order and relative sizes of the orbits.
  3. It was putting an end to the chronic debate on the order of Mercury, Venus and Sun.
  4. It was illustrating a harmonious relation among the distance of planets and their apparent retrograde motion.

However, this argument could not prove that Copernican system was the true model. None of the advantages counted above could persuade his contemporary realists that his system was more likely to give a true account of how the planets actually move. Copernican system could be simpler, more elegant, and harmonious, but this did not prove that it should be the true account of planetary system. Let’s evaluate each superiority regarding its evidential power for the actuality of the system. Sure, from the perspective of Copernic’s contemporary realists.

It, ultimately, does not need epicycles and eccentrics.

Later modifications of the original model by Kepler will give this advantage. But, even this does not prove its truthfulness, as we will discuss in the following paragraph.

It suggests a simpler and “more natural” model of the motions of inferior planets.

So what? There are many complex processes and systems in the nature. A simple explanation does not mean it is the reality. The motions of inferior planets can be well synchronized naturally. There are some interesting natural phenomena which we are not able to explain. For instance, Sun is much bigger than the moon. However, proportion of their volumes is exactly compensated by their distances. Both occupy the same apparent space in the sky. The harmonious relation between their size and distance is a unique coincidence. Then, why the same harmony should not exist between the center of epicycles of inferior planets and the motion of the sun? In addition, we do not see the other side of the moon. If you are consistent with your “simple is more natural” theory, you should find an explanation for this synchrony. The reality cannot be determined by the number of assumptions we have. A theory with less assumption may be more convenient to use and more credible, but it does not prove that it is the reality.

It puts an end to the chronic debate on the order of Mercury, Venus and Sun.

Well, this also does not mean that it is the true account of the planetary system. Can you suggest any scientific or logical reason that Mercury, Venus and Sun cannot complete their journey around the ecliptic at the same time, that is 1 year? If you cannot do this, then you must admit the possibility of triple synchrony. If they are synchronized, then, your model will not show the real order, instead it will determine an order that satisfies your assumptions.

It illustrates a harmonious relation among the distance of planets and their apparent retrograde motion.

Indeed, the Copernican system provides a reasonable explanation for this case. However, we cannot be sure that this is the only possible explanation. There may be other explanations which will not require sun to be in the center. Or, this may be just a coincidence, like many others.

Moreover, a realist would raise a serious doubt about Copernican model by pointing to the lack of stellar parallax (since, there was no instrument to observe stellar parallax at that time.) This doubt could be eliminated by assuming a universe 75 times bigger than Al-Fargani’s. But, only by assuming!

Yet, Copernican system was accepted enthusiastically before it was proven. The intellectual and psychological condition of Europe was pregnant to this idea. People could not wait for the proof. Its scientific advantages and its inherent political message was enough to allure most of the scientists. It supplied a board and a frame for the colorful dreams of scientists who were frustrated with the old system and theology.

The reasons that we mentioned in the beginning and some other reasons caused a shift in paradigm. The water was hot. It needed a candle in the right place to boil. It was not important whether the candle was real or superficial. It was needed.

Fortunately, it was found later that the candle was real; it was from wax.


PS: This article was written in 15 November 1992 by Edip Yuksel for Phil 123, Philosophy of Science thought by Professor Richard Healay