Aristotle has caused a lot of trouble

Galileo’s first trouble with authority was not with the church ^[1], but with the philosophers. As we read in Timothy Ferris’s book Coming of Age in the Milky Way: ^[2]

Galileo was twenty-five years old when a scientifically inclined nobleman, Francesco Cardinal del Monte, took an interest in his abilities and got him appointed professor of mathematics at Pisa. There he lectured on astronomy, poetry, and mathematics and resumed his hectoring of the Aristotelians, at one point circulating a satirical poem poking fun at the Scholastics’ habit of coming to school in togas, like little wax Aristotles. The students were delighted but the Scholastics were in the majority on the faculty, and when Galileo’s contract expired he was let go.^[3]

It is often argued that medieval Christianity delayed the development of science, which while exaggerated by the critics of Christianity may be at least partially true. ^[4] But as the Dark Ages ended, the renewed adoration of Aristotle caused, at the very least, unnecessary additional delays. Aristotle’s horrible science was considered by many (the scholastics mentioned above) as beyond refute, solely because of its pedigree. However what Aristotle taught, when it comes to science, was nonsense. Probably the best example is that he taught that the starry realm beyond the “air” (outer space, if you like) was absolutely immutable.

Then, praise God, we have the suddenly appearing supernova of 1572 ^[5] which closed the door once and for all on Aristotle's "science". The scholastics, you see, would have it that something that appeared out of nowhere had to be a close-by atmospheric phenomenon, not far away in the Aristotle's immutable aether. But the development of triangulation demonstrated beyond any doubt that the supernova was not in the atmosphere, but distant, among the stars.^[6] When Aristotle's "so bad it is not even wrong" view of the cosmos was finally jettisoned, scientific progress took off on an exponential trajectory.

Another aspect of the discipline of philosophy that Galileo objected to was its penchant, still evident today, for proof by an appeal to authority. (In some sense one feels for them, what other arrow do they have in their quiver?) Ferris quotes a passage from a book written by Galileo's father that might well have been Galileo's motto:

It appears to me that they who in proof of any assertion rely simply on the weight of authority, without adducing any argument in support of it, act very absurdly. I, on the contrary, wish to be allowed freely to question and freely to answer you without any sort of adulation, as well becomes those who are in search of truth. ^[8]

The problem with Galileo, as Ferris points out, is that while he had a laudable disdain for relying on arguments from authority, he reached a point in his life where he demanded that others accept his conclusions on precisely that basis. That's what got him in trouble with the church, not his support of heliocentricity.

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^[1] And his trouble with the church was not really about his Copernicanism, but rather because he was an arrogant jerk and a political imbecile. He actually had important supporters in the church early on, but he got too full of himself.

^[2] A great read which I use in my Honors course on the history of physics.

^[3] Ferris, Timothy. Coming of Age in the Milky Way (p. 85). HarperCollins e-books. Kindle Edition.

^[4] Another reason is the Romans loved engineering, but not so much pure science, and their influence lasted well beyond their empire.

^[5] It cannot be overstated how important to modern science was the 1572 supernova, only to be followed a scant 32 years later by another supernova, so that both Tycho Brahe and Kepler had ample viewing opportunities. There would not be another one visible to the naked eye until my lifetime. It was in 1987. Some see luck, I see providence.

^[6] Because the super nova looked like it was in the same place to observers that were far from one another, just as stars do. If it were in the atmosphere it would have looked very different for distant observers (not even that distant) against the background stars.

^[7] The modern scholastics still get immutability wrong, not of the cosmos but of God, and like the physical error eradicated by the 1572 supernova, the theological error is traceable to Aristotle. His damage continues, with a common view of divine immutability as much closer to Aristotle's distorted view of God than anything found in the scriptures.

^[8] Ferris, Timothy. Coming of Age in the Milky Way (p. 84). HarperCollins e-books. Kindle Edition.