Hypothesis in science. The 550^th anniversary of the birth of Nicolaus Copernicus

It is sometimes assumed that the heliocentric (Copernican) and geocentric (Ptolemaic) systems were considered to be equally valid for a long period of time. On the contrary, there are descriptive, and (at least in part) predictive differences between the two models. These differences became even more substantial after the discovery of the telescope. The availability of considerably more new observations and data forced astronomers to abandon the Ptolemaic system, which was no longer able to justify certain physical observations. Rather than the geocentric, it was the geo-heliocentric model (proposed by Tycho Brahe) which became the real antagonist to heliocentrism, since the latter model was able to justify the motions of celestial objects based on observational evidence. However, for geometric description to also provide an explanation, astronomy needed to change its disciplinary goals. This happened when Newton proposed universal gravitation as an explanation for Kepler’s elliptical orbits. When Kepler’s description of these orbits was combined with Newton’s explanation, the geo-heliocentric model lost even more explanatory power, while the heliocentric model was reinforced.

If certain astronomical models and their equations can provide nothing more than an empirical description of the explanandum, then one may seek to provide the answer to the following question: could it be that in the geometrically-based astronomical models mentioned above there is something that helps us to distinguish merely descriptive from explanatory models? Since mathematical dependencies of scientific theories do not necessarily specify the causal dependencies that produce the explanandum, we probably do not know whether our hypotheses correctly describe the world. Thus, those hypotheses are nothing more than useful tools with which to organise observational data. However, just because a certain model or hypothesis is non-explanatory does not necessarily mean that it cannot play any descriptive or predictive role. What criteria do we have then to evaluate our scientific hypotheses, models or theories?

Our conference aims to address the role of hypothetical thinking in the formulation and development of scientific theories and models.