Friday, March 20, 2009

Galileo Galilei

Since today is the equinox, and our thoughts ought to turn to the turning of the earth in its ellipse around the sun, we might think of a Catholic astronomer who thought otherwise.

Yes, today we shall recall Galileo Galilei, who did more than some recall, and less than some credit him with.

He was born in 1564, and died in 1642, which was the year that Newton was born.

He was a good scientist - ins some things. He was also Catholic - he did not deny the truths of the faith - but he sure was stubborn, and fat-headed, and in at least some sense a very naughty man. He did not say "Eppur si muove" = "And yet it moves" - that was invented by a certain Abbé Irailh about a century later. He did not drop stuff from the Leaning Tower of Pisa. And no, he was not condemned, and burned at the stake.

About the earth's motion, I am sorry to say that he did not get the science right. Galileo would not listen to Kepler, who had the data, and formulated what we call Kepler's laws of planetary motion - but Galileo would not listen to anyone it seems. Galileo said he had "proof" - but his "proof" was wrong, and his fellow scientists told him to his face he was wrong, and he would not listen.

To put it in a brief sentence, "Galileo was a tiresome person" [Windle, The Catholic Church and Its Reactions With Science]

But enough of the negatives. Galileo did some very important and groundbreaking work in observation - the mountains of the Moon, the spots which revealed the rotation of the Sun, the phases of Venus, and the four large moons of Jupiter, still called the Galilean moons: Io, Europa, Ganymede, Callisto.

And as it turns out, though Galileo was wrong about his science of the earth-around-the-sun issue, he happened to be right about the theology - which is hilarious, considering at one point he was dealing with St. Robert Bellarmine, a Doctor of the Church! I am not going to write a whole book on this, but here's just a little from Jaki: was Galileo and not Bellarmine who quoted Jerome and Augustine to the effect that biblical references to the sun's motion and to the earth's immobility may be a mere registering of appearances.
On a cursory look it may be said, and unfortunately this has been done all too often, that the Church of Urban VIII and Bellarmine understood Galileo's science much better than Galileo did. Both those churchmen, and many others after them, took exception to the realism with which Galileo asserted the heliocentric ordering of planets. According to them the heliocentric theory, or any physical theory for that matter, was nothing more than a convenient ordering of data with no intrinsic bearing on reality.
Heliocentrism, as proposed by Galileo, was a vision. Its chief empirical evidence, the observation of stellar parallax due to the orbital motion of the earth, was still two hundred years away. Galileo also held that no experiment performed on the earth can serve as a proof of its motion. Two centuries later Foucault proved him wrong. Worse still, Galileo was the kind of visionary who at times could not see his own self-contradictions. For more than twenty years prior to the publication in 1632 of his Dialogue concerning the Two Chief World Systems he kept hinting that he had worked out such a proof. The proof, based on the tides, was presented by Galileo in the fourth part of the Dialogue where in the first three parts he repeatedly stated the impossibility of a terrestrial experiment on behalf of the earth's motion. Within a year it was stated in print that Galileo's proof was based on a confusion between two coordinate systems, one pivoted on the earth's center, the other on a point of its surface.
[Jaki, Catholic Essays]

Even physics, which corresponds most closely to that definition of science, is not about motion, not about things, but only about the quantitative aspects of things in motion. At the same time science alone is competent about those aspects. And those aspects are everywhere. This is why science is all important, though not exclusively important.
From this there follows something most momentous for handling properly the subject of science and religion. This most momentous point was already noted by Saint Augustine when he tried to cope with the obvious differences between what one learns from the Bible and from science about the physical world. By Saint Augustine's time it had for seven hundred years been generally accepted in educated circles that the earth was spherical. But according to the Bible the earth is a shallow disk floating on waters. To reconcile this difference, Saint Augustine laid down an all important rule: whenever something in the Bible about the physical world conflicts with what reason established on the same point, the Bible should be reinterpreted accordingly. About things physical, or at least about their shape, reason or science is the final arbiter.

[Don't forget:] In Augustine's time every educated person knew that the earth was spherical, whereas according to the Bible the earth is more or less a flat disk.
[Jaki, A Late Awakening]
The work of St. Augustine referred to is De Genesi ad litteram:
There Augustine laid down the rule that whenever reason established with certainty this or that feature of the physical world, contrary statements of the Bible must be interpreted accordingly. One reason for obeying that rule was to prevent the Creed from being turned into a laughing stock for unbelievers, who, as Augustine stated, often happen to know “with absolute certainty and through experimental evidence about the earth, sky, and other elements of this world, about the motion, rotation, and even about the sizes and distances of stars, about certain defects [eclipses] of the sun and moon, about the cycles of years and epochs, about the nature of animals, fruits, stones, and the like.”
Augustine assigned indeed a very generous extent within which scientific knowledge could have absolute certainty. At the same time he allowed no range whatever within which there could be, about natural phenomena, a “Christian account” in opposition to what could be known by science. He viewed such accounts as “most deplorable and harmful, and to be avoided at any cost,” because on hearing them the non-believer “could hardly hold his laughter on seeing, as the saying goes, the error rise sky-high.”
[Jaki, Bible and Science]
But this is beginning to go off the topic and onto another one. Some other time we'll go further.

See here for more, and also the books by S. L. Jaki, for example, especially "The Case for Galileo's Rehabilitation" in Catholic Essays, "Myopia with Lynx Eyes about a Text of Aristotle" in A Late Awakening, and The Relevance of Physics, just to start with.

I must add one more thing: whenever someone tries to pester you with the name "Galileo", merely reply "Pasteur".


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