Galileo and Fellow Astronomers’ Erroneous Scientific Beliefs

Stories of Galileo’s “torture” are myths invented and proliferated by a strange alliance of anti-Catholic fundamentalists and anti-religion skeptics.

Cristiano Banti, “Galileo Facing the Roman Inquisition,” 1857
Cristiano Banti, “Galileo Facing the Roman Inquisition,” 1857 (photo: Public Domain)

Why is it that one always hears about the notorious trials of Galileo and the errors made by (one faction of) the Catholic Church (on a sub-magisterial, sub-infallible level) about science in the early 17th century, but never about Galileo’s own misguided dogmatism in some areas, and several flat-out errors?

Some of these were held by Galileo even in the face of current superior research from other scientists and thinkers, like Johannes Kepler. The Catholic Church made a mistake. We’ve admitted it; we no longer deny the truth of heliocentrism, etc.

Most Catholics in that early period of modern astronomy didn’t get everything right, but neither did anyone else (including even the best scientists) get even some very basic facts of astronomy right. So why is one party excoriated, while the errors of the vaunted (and indeed brilliant) scientists are ignored, unknown, or suppressed, in a cynical effort at one-sided presentation?

Let me present, if I may, some basic facts from the history of science:

Copernicus (1473-1543) erred in asserting circular orbits and in holding that the sun was the stationary center of the universe, with not only the earth and the other planets of the solar system, but also all the other stars, moving around it. Galileo followed him in these beliefs. He also believed that transparent rotating crystalline spheres carried the planets in their orbits.

Much later, astronomers William Herschel (1738-1822) and Friedrich Bessel (1784-1846) showed how the sun was not the center of the entire universe.

Tycho Brahe (1546–1601) erred insofar as he was a geocentrist and held that the sun and moon revolve around the earth, and the other five planets revolve around the sun: all in circular, not elliptical orbits. Also, in his system the earth did not rotate.

Johannes Kepler (1571-1630) was correct in asserting elliptical orbits of the planets around the sun, at varying speeds (both notions having been foreseen by the Catholic Cardinal Nicholas of Cusa in the 15th century), but continued to err in thinking that the sun was the center of the entire universe. 

Galileo (1564-1642) disbelieved in Kepler’s elliptical orbits of the planets, ten years after Kepler published his third law of planetary motion, and considered the circle the “perfect” and “beautiful” shape for planetary orbits. Einstein described this mistaken view as “a grotesque illustration of the fact that creative individuals are often not receptive.”

Belief in the sun as the center of the entire universe (held by Copernicus, Kepler, and Galileo alike) is not all that different (knowing how large the universe is) from positing that the earth is the center. Both are vastly erroneous positions. But, oddly enough, we only hear about one historical error (from the Church) and not the other (from these eminent early scientists).

Galileo, moreover — over against the treatise on the comets of 1618 by Jesuit mathematician Orazio Grassi — vehemently  argued in his 1623 book The Assayer that the comets of 1618 were merely an optical illusion. 

Galileo thought that the oceans’ tides were caused by the rotation of the earth and  dismissed as a “useless fiction” the idea, held by Johannes Kepler, that the moon caused them.

Galileo (like Kepler) was an avid proponent of astrology (while Aquinas and Augustine had rejected it some 400 and 1200 years earlier). He wrote in a letter to Piero Dini (21 May 1611):

If, therefore, of the inferior causes, those which arouse boldness of heart are diametrically contrary to those which inspire intellectual speculation, it is also most reasonable that the superior causes (if indeed they operate on us) be utterly different from those on which courage and the speculative faculty depend; and if the stars do operate and influence principally by their light, perchance it might be possible with some probable conjecture to deduce courage and boldness of heart from very large and vehement stars, and acuteness and perspicacity of wit from the thinnest and almost invisible lights.

In his astrological chart for his oldest daughter, Virginia, he wrote: “Saturn signifies submission and severe customs which gives her a sad demeanour, but Jupiter is very well with Mercury, and well-aspected corrects this.” But Galileo’s famous critic and judge, St. Robert Bellarmine, never believed in astrology, and thought that God’s providence — not the stars — guided mens’ lives.

Bellarmine also had made it clear that heliocentrism was not irreversibly condemned, and contended that an inadequately proven theory was not an unassailable fact. Thus (irony of ironies!), he actually had a better understanding of the nature of a scientific hypothesis than Galileo, who was overconfident and obstinate in dogmatically proclaiming his scientific theory as absolute truth. His telescope observations did not establish heliocentrism beyond any doubt. It wasn’t actually proven until some 200 years later.

Bottom line: Galileo was not always right and the Church always wrong in the famous confrontation. Eminent philosopher and historian of science Thomas Kuhn (hardly a Catholic apologist) observed:

Most of Galileo’s opponents behaved more rationally. Like Bellarmine, they agreed that the phenomena were in the sky but denied that they proved Galileo’s contentions. In this, of course, they were quite right. Though the telescope argued much, it proved nothing (The Copernican Revolution, New York: Vintage Books/Random House, 1959, 226).

Lastly, is it true that Galileo was tortured and maliciously handled by the Church? No! In 1633 Galileo was “incarcerated” in the palace of one Niccolini, the ambassador to the Vatican from Tuscany, who admired him. He spent five months with Archbishop Piccolomini in Siena, and then lived in comfortable environments with friends for the rest of his life (although technically under “house arrest”).

No evidence exists to prove that he was ever subjected to torture or even discomfort until his death nine years later. Nor is there any evidence, as another myth goes, that he was deliberately blinded (he lost his sight naturally in 1637). Stories of Galileo’s “torture” are myths invented and proliferated by a strange alliance of anti-Catholic fundamentalists and anti-religion skeptics.