Role in Science History
In this section we will look at the role that the change from the earth-centered view of Aristotle to the sun-centered view played in the history of science. In the process we will gain more insight into the nature of science and how it works.
Most historians of science agree that what we call modern science originated in Europe during the 16th century. This is somewhat surprising since the European society at that time was not nearly as advanced as the Greek, Islamic, and Chinese cultures of the past. The question then is “ Why Europe?”
The main thing that separates science from previous approaches to the study of the natural world is the emphasis on observation and experiment. The Greeks, for example, relied primarily on reason and placed little value on experiment. The emphasis on observation arose, at least in part, from the Christian Faith that was dominant in Europe at this time. A central Christian belief is that God created the heavens and the earth starting from nothing. Thus, God was free to design any kind of universe that he desired. It follows that logic alone cannot discover what was in the mind of God. To discover the nature of God's creation, it was necessary to look and see, i.e., observe and experiment.
The story presented in this paper took place in the early days of the scientific revolution. We can see the importance that observational data played in replacing the earth-centered views of Aristotle by a sun-centered view. It was Galileo's observations with his telescope that exposed some of the problems with the Aristotelian view. It was Tycho Brahe's accurate astronomical data that led Kepler to his laws of planetary motion. Much later, it was Bessel's measurement of stellar parallax that firmly established the sun-centered view.
The story presented here also shows that the interpretation of observational and experimental data is not neutral but can be influenced by philosophical considerations, i.e., the observer's worldview. Although many aspects of Aristotle's view of the natural world were based on reason rather than observation, there were some aspects of his viewpoint that seemed to agree well with our observations, e.g., It didn't feel like the earth was moving since you didn't feel any of the effects (such as air flow) that are normally associated with motion. In addition, there was the failure to observe stellar parallax and the difficulty in moving massive objects. It was considerations such as these that delayed the acceptance of a sun-centered view. It was not until Galileo, Kepler, and Newton provided a different conceptual framework that the observations that seemed to support an earth-centered view could be interpreted differently.
Scientists, like everyone else, have their biases, and live in a society where there are shared beliefs about the natural world and how to study it. We like to think of science as dealing with purely factual data, but bare facts have little use without some interpretation. Throughout history, the major advances in science have not depended so much on new or better data, but on new ways of viewing the data: new conceptual frameworks.
The history presented here also illustrates the interplay of data and theories. Theories are based on certain assumptions or hypotheses. Predictions are then derived from these hypotheses that are tested against experimental or observational data. It is rare that the hypotheses themselves can be tested directly, but it is predictions based on these hypotheses that are tested. If a theory consistently makes verifiable predictions, it is often labeled a law. Kepler used his laws to make tables of planetary predictions that were later confirmed by observation.
You can also see from this example that major changes in science often require a considerable amount of time and usually face considerable resistance prior to their acceptance. I hope this gives you a better appreciation of the important role that this piece of history played in the advancement of science.
+++++