Arguments For and Against Astrology: From Copernican Revolution to Free Will Debate

Arguments for and against astrology. The greatest supporters and advocates of the Copernican model have never found any dissonance or antinomy between this model and astrological practice. Starting from Rheticus himself who placed in his Narratio Prima, the preview of Copernicus's De revolutionibus, a series of astrological and numerological considerations, arriving at Kepler and Galilei, the two main supporters and advocates of the Copernican system, who also dedicated a large part of their lives before and after conversion to Copernican heliocentrism to the study of Astrology, without ever finding any contradiction with it. In particular, Galileo himself reassures an old student, Monsignor Piero Dini, that the validity of astrology is not undermined by the passage from a geocentric to a heliocentric system. The Copernican Revolution, therefore, if it can be considered an adjuvant and a catalyzing element, cannot be considered the true engine of the process that led to this internal revolution at the base of the science of stars.

• The affirmation of the experimental method: another common anachronism is to attribute the astrological-astronomical paradigm change to a natural passage due to the affirmation of the experimental method that would have thus rapidly denied the fanciful astrological assertions by invalidating the theory. Although this vision also contains elements of validity, it is also true that it does not completely account for the situation. We must not forget that al-Kindi himself repeatedly affirms in various points that his hypotheses have been confirmed experimentally. When Pico della Mirandola, a firm rejecter of astrology's predictive capabilities, died before completing his thirty-third year as predicted by Licio Bellanti's astrological prediction, it was simply thought that his Disputationes adversus astrologiam divinatricem had been disproved by facts. The missed Universal Flood of 1525 is countered by the prognosis of a barely twenty-year-old Cardano who declares an epidemic for Milan to Duke Francesco II Sforza, which punctually occurred. In practice, the criterion of experimental negation does not apply to Astrology. Similarly, the concept of experimental verification takes on entirely particular connotations in the astronomical field. As Heisenberg correctly highlights, the Copernican revolution denies an immediate fact, experimentally verified every day, such as the centrality of the earth and the rotation of the sun, by virtue of a superior unitary principle such as a single law of gravitation that regulates the motion of stars. Heisenberg's position is certainly provocative but highlights an important side of the astronomical question. Even without falling into Feyerabend's excesses, however, we must recognize that the Copernican position was not more in agreement with experimental data than the Ptolemaic one, at least until Kepler's Harmonices Mundi. In Astronomy more than in any other discipline, experimental data are difficult to replicate and lend themselves to multiple interpretations, ad hoc hypotheses created, etc. The discourse therefore of abandoning Astrology as not colliding with experimental data by virtue of an experimentally exact and indubitable Astronomy is partially acceptable, but also in this case appears a secondary phenomenon, an effect of the formation and separation of Astrology from Astronomy rather than its cause.

• New instruments: in the same direction as the previous point is inserted the discourse relating to the series of instruments that are developed and perfected in this period and that lead to a substantial improvement in astronomical observations. This element, while strengthening astronomical practice, however, does not provide it with an autonomous identity, independent from other disciplines such as navigation, agriculture and medicine, therefore it cannot be considered the engine responsible for the epistemological revolution at the base of Astronomy. Similarly, the new conceptual tools implemented by Galileo, Kepler and Newton do not per se provide a new purpose to Astronomy but perfect its ability to respond to the old ones.

• Particular astronomical events: special attention in this context must be reserved to the observation of Tycho Brahe's Stella Nova in 1572. The importance of Tycho Brahe is not in this context due to the actual observation of the star which had been observed anyway by John Dee, Thomas Diggs, Francesco Maurolico and others. Tycho Brahe's role, however, was to consider such an event as experimentally significant also in its philosophical implications. This in a certain sense represents an anticipation of what Kepler will carry out in a more systematic and complete way in Harmonices Mundi by providing a new purpose and methodology to Astronomy. All these elements, while being important and not negligible relative to the formation of Astronomy, are however secondary compared to the role that in this context some themes have operated that have radically changed the foundations and way of understanding Astrology. Among these, the most important and most significant is decidedly the polemic and debate relating to Free Will. One cannot ignore how the debate on Free Will undermined the reliability of judicial astrology which at the time was considered almost infallible, nor how the decision made in the Council of Trent to combat fatalistic astrology influenced the decline in non-ecclesiastical publications of astrological predictions, and with a polarization of studies and writings towards a doctrinally more prudent reality like Astronomy. To this phenomenon must also be added and associated the phenomenon of the spiritualization of astrology which starting from the 16th and 17th centuries, combining perfectly with the debate relating to free will and merging with neoplatonism and nascent hermeticism spreads pushing towards a change in the purposes of astrology which pass from being primarily divinatory to being primarily philosophical and spiritual. An emblematic case is represented by Cornelius Agrippa, who despite dedicating numerous pages to astrology in his Occult Philosophy, however refuses to draw up the horoscope for the future.