A scientific theory is as close to "truth" as you can get. "Theory" doesn't mean some random idea that just popped into someone's head.
First of all, as to the Copernican system, it was PROTESTANTS who railed against it, NOT Catholics. The Catholic Church never censured the theory or its teaching until the problems with Galileo emerged.
Galileo's initial work was actually WELCOMED by the Church. This work WEAKENED the Ptolemian system, but this was of no concern to the Church. Galileo was even ENTHUSIASTICALLY greeted by the Pope in 1611 because of his work. Jesuit astronomers were also confirming many of Galileo's discoveries. The Church wasnt hostile to Galileo's work, it was ACTIVELY SUPPORTING IT!
Pope Paul V and the Jesuits honored Galileo for his work. When he first published his evidence in support of the Copernican system, he received PRAISES from the Church, all the way up to the Pope, for his work, as well as a Cardinal who would become Pope Urban VIII. A modern scholar on the subject by the name of Jerome Langford says that the proof at this point was INSUFFICIENT to "win the allegience of open-minded men." Langford also pointed out that Jesuit astronomers had confirmed his findings.
Langford also notes that Galileo was also to blame for what later happened to him. "(he) entered the debate without sufficient proof..." It was PROTESTANTS who led charges that Galileo's theories violated the Bible, though Catholics were sensitive to those charges. However, unlike Protestants, Catholics were not closed to what these ideas signified. Cardinal Robert Bellarmine noted that "...we should proceed with great circumspection in explaining passages of Scripture which appear to teach the contrary, and rather admit that we did not understand them than declare an opinion to be false which is proved to be true." Saint Albert the Great concurred with this opinion.
In 1616, the Church told Galileo that he was free to teach the ideas as a hypothesis (which is all it was at that time), and he agreed. He continued his work WITH THE SANCTION OF THE CHURCH! Eight years later, he was again received warmly by the Pope and other Church leaders. Pope Urban VIII told him that the Church had NEVER declared the Copernican system to be heretical.
Galileo published
Dialogue on the Great World Systems was published in 1632 WITH THE URGING OF THE POPE! His problem was here he ignored the restrictions on teaching it as a hypothesis and posited it as an established truth (which it had NOT been at that point in time.) There is no reason to believe that he would have encountered any problems with the Church had he treated his ideas as the hypothesis that it was.
In 1633, he was declared suspected of heresy and ordered to desist from publishing. This wasn't the best decision of the Church, however, he did violate his agreement. However, to say that the Church persecuted Galileo is a grave overstatement. Catholic commentators throughout the 17th century repeated that Galileo's ideas were NOT heresy and that interpretations of Scripture were only binding on Catholics if they were agreed to at a general Church council. Catholic scientists continued to make scientific inquiries into a "moving earth" after 1633.
Yes, threatening a man with execution for teaching the truth was a "reasonable" stance. Who in today's world would you like to see the Catholic Church execute for their words? :roll:
When did the Church threaten to execute Galileo for "teaching the truth?"
Baloney. Galileo had plenty of evidence; the geocentric model of the solar system had been falling apart long before Galileo came along anyway.
But it was far from universally agreed to by educated and reasonable men of the era, as noted by Professor Langford.