Introduction
Modern science can be said to have its roots from the Copernican theory, though it was received with uncertainty by the Copernicans prior to the seventeenth century (Curd 3). Most of the scientists in the sixteenth century believe Ptolemy’s theory of Earth-centered astronomy, as well as Tycho Brahe’s theory of Geoheliocentric system. The reluctance of early scientists in accepting the Copernican theory makes their later approval raise a few questions about the other theories (Curd 3).
One big question posed by this shift of mind is why and when the Copernican theory gained approval over the Ptolemaic theory. Current reviews of the ideas previously adopted as explanations of the change of beliefs have been found to be unsatisfactory. The Copernican theory had been found to be more precise in its forecasts and clear-cut than the Ptolemaic, which is not the case today (Curd 3).
Reasons for accepting the Copernican theory
One of the reasons as to why the Copernican theory was accepted is that it satisfied the “taste” of people, who disregarded rationale and facts. This harsh conclusion by Thomas Kuhn was challenged by Zahar and Lakatos, who argued that the research undertaken for the Copernican programme was empirically precise (Curd 3). The empirical progression of the Copernican theory was based on its essential geometric configuration, which had adequate projecting capabilities.
Lakatos and Zahar later edited the conception of a novel fact, stating that it was not necessary for it to be unfamiliar, but it should not have been acknowledged in the formation of the theory (Curd 3). Glymour was also in support of the Copernican theory, compared to the Ptolemaic one, stating that the latter was objectively inferior. The superiority of the former theory was observed in its capability to validate and be analyzed by the facts of that time based on positional astronomy (Curd 4).
Comparing the Heliocentric and Ptolemaic theories
Support on the validity of the heliocentric theory has been from various scientists, like Millman and Hall, who found it satisfying before the discoveries by Newton and Galileo (Curd 4). The book on testing and confirmation of theories by Glymour looks at the two theories comparatively; that is the geocentric and the heliocentric theories.
Glymour and Zahar believe to have been contributors to the understanding of the heliocentric theory, in terms of its methodical logic, harmony and accord, as expressed by other authors like Rheticus, which is contrary to the belief that the theory was irrational, as put forward by Kuhn (Curd 4). One way to compare the two theories is by using the equation (1),
- 1/T p = 1/T e -+ 1/S p where T is the heliocentric period of planet P, Te is the heliocentric period of Earth and S is the time interval between successive episodes of retrograde motion as viewed from earth. When the planet is superior, the – sign in the equation is used, while + is used for an inferior planet (Curd 5).
Inferior planets are Mercury and Venus. The Copernican theory works with an excess of three planets on the superior side, while the Ptolemaic theory works with the superior planets only. The Ptolemaic theory also fails to explain the relationship between the motion of the planets and the solar component.
The Copernican theory offers various explanations unlike the Ptolemaic theory (Curd 5). One of the things enlightened by the Copernican theory is the progressively diminishing value of S, as the distance of the planet from earth increases, irrespective of the direction (Curd 5).
The limits of the Ptolemaic theory do not allow for the determination of the displacement of planets from earth. Aristotle defended one of the theories in the Ptolemaic theory that states that the period of a planet is proportional to the size of its orbit (Curd 6). In the heliocentric theory, the distances are obtained with reference to the distance between the planets and centre of revolution, which is actually the sun.
These displacements that are predetermined are used as a basis for the order assignments, which is an indication of harmony and order, characteristics of Copernican theory, and lacking in the Ptolemaic theory (Curd 6). Bases on the tests conducted between the two theories, the Copernican theory emerges as the better one with greater explanatory power. The tests were based on the same positional data (Curd 6).
The Tychonic theory
The Copernican revolution was defined as the change of belief from the Ptolemaic theory to the Copernican theory. The revolution was dependent on two decisions namely the denunciation of the Ptolemaic theory as untrue, and the recognition of the Copernican theory as correct (Curd 6).
The prudence of either choice is not explained by the positional data due to the effect of two factors namely the Tychonic theory, a third alternative theory, and the existence of vital drawbacks to the Copernican theory. The Tychonic theory was published towards the end of the sixteenth century by Brahe. This theory suggests a geoheliocentric array whereby the earth is static and at the centre (Curd 6).
The sun and the planets are said to revolve around the earth. Therefore, the planets have the orbit of the sun as their deferent, and their major epicycle is the heliocentric orbits. Unlike the Ptolemaic theory, the Tychonic system is comparable to the Copernican theory, both kinematically and geometrically (Curd 6).
The Tychonic theory is like the Copernican theory in that in spite of its two centers of revolution, it provides for the derivation of equation 1, and the calculation of the displacement of the planets from the sun (Curd 7). The Copernican theory had two main problems namely the perceptible proof that the earth is static, and the lack of noticeable stellar parallax.
These problems were unique to the Copernican theory, since the other two theories were geostatic. The scientists in support of the Copernican theory argued that the two problems were contradicting with the requirements of the theory, which are two terrestrial motions. The writings of Galileo, in the early seventeenth century were sufficient to disregard the Ptolemaic theory, though the issues in the other two theories remained (Curd 7).
Semi-Tychonic systems appeared in the 16th and 17th centuries and believed that the earth rotated, but did not revolve around the sun (Curd 7). The semi- Tychonic theory was accepted since it enjoyed similar merits with those of the Copernican theory, as well as its simplicity, which made sure to ignore the independent motion of every celestial body. This was especially beneficial in its acceptance after the discovery of Newton’s first law of motion, which defines the forces that maintain a body in circular motion (Curd 7).
Conclusion
The acceptance of the Copernican theory was supported by both observation and acceptance on its scale of rationality as was seen in the Tychonic alternatives (Curd 8). One deduction observed in the determination of the validity of the theories is that the scientists who support the law focus a lot of their energy and time to build on it, and therefore defend it from harsh criticism, and non-believers (Curd 8). The justification of any theory is only dependent on scientific analysis, to solve any mysterious questions and doubt in people (Curd 8).
Works Cited
Curd, Martin V. “The Rationality of the Copernican Revolution.” PSA: Proceedings of the Biennial Meeting of the Philosophy of Science Association (1982): 1, 3-13.