I often hear that the rate of innovation was very high during ancient times in Greece and the Roman empire. I've also heard that the rate of innovation was reduced once the Catholic Church gained strength. Is there any clear evidence to support (or disprove) this?
It would be very interesting to see a chart of rate of innovation over time in western civilization.
Of course, this begs the question of what is "innovation". Do you count number of inventions? Do you give more weight to inventions that would have long lasting significance through history? Or ones that may have been less influential but providing a huge impact at the time? Or ones that represented great leaps in intellect? Do you count scientific discoveries as innovations if they had no immediate tangible effect on society?
For instance, the Romans were quite influential and important in Western history, but they certainly did not have anything resembling an R&D department (perhaps excepting in the gladiator pits). Yet they were skilled at productizing other civilization's innovations. Due to their omnipresence and the long duration of the empire they can be credited with a number of innovations yet I would still score their rate of innovation as quite low.
The Dark Ages following the Roman Empire (very roughly 500-1000 AD) were a time of low innovation certainly. A lot of knowledge simply disappeared during these times. This had nothing to do with religion however, and more to do with socio-political factors. If anything, the Irish monks deserve a huge share of credit for their work transcribing greek texts to keep that learning alive in the west.
The Middle Ages (loosely 1000-1500) in contrast were a period of increasing innovation. Part of this was rediscovering or relearning from the past, and I think they deserve credit for this! But this period also brought a number of completely new traditions in agriculture, art, medicine, economics, mathematics, politics, and so on which form the foundations of society today.
What role did the Church play during this period? If anything I would have to credit them as a promoter of innovation, or at least of higher education. The Catholic Church in this period was the only source of advanced education, and in fact many of the earliest philosophers, mathematicians, and proto-scientists were themselves clergy members. Much of the greatest art, sculpture, literature, and science of this middle period was arrived at due to the patronage of the church.
Galileo serves as a turning point. But I think it has less to do with him specifically, nor his particular findings, than the general trend of scientific skepticism and inquiry that Galileo and his peers represented, and the evolution of society to a more heterogeneous R&D environment. More specifically, prior to the invention of the printing press, transmission of knowledge depended upon scribes - of whom the Church had a distinct monopoly; with the printing press, they quickly lost that monopoly and had to resort to more conspicuous methods of exerting authority.
A demarcation point can also be found here. Prior to this, the general consensus of Church intellectuals would be that all philosophy, science, and mathematics could be derived to the Will of God. Any study of these topics could be equated to a study of God Himself. But at this point there was a general view that further investigation into these topics would serve to diminish God or at least increase questioning into His existence.
The Scientific Revolution, which followed the Middle Ages and was more part of (or at least foundation of) the Renaissance, saw the increased involvement of the Church as a reactionary suppressor of innovation. Questions continued to be raised that organized religion could not effectively answer. Thus, organized religion quite naturally shifted to a more suppressive relationship with knowledge. And that's what we tend to remember today.
As negative as I am on the Roman Catholic Church in general, I don't think they can be credited with anything more than a modest influence. In a few specific periods they were definitely detrimental, but in other periods they had a strong positive force.
Quite the contrary as Rodney Stark pointed out in The Victory of Reason - the Catholic church itself promoted most of the societal conditions that allowed the Middle Class to take hold, and in so doing also promote the nurture of science and industry.
Chief among these were personal property rights (stemming from the idea that we were God's stewards) and equality before God in all judicial matters (hence the rule of law). The ideas for patent and copyright also come out of respect for the Imago Dei in all men.
Stark also points out the explicitly Christian roots of the Renaissance, which stemmed from a religious effort to go ad fontes - back to the sources - first of Christianity (hence the glorification of Rome), then to the society in which Christianity flourished.
Stark spends a great deal of time talking about the factors that eventually led Southern Europe (Catholic) to eventually decline after the Reformation - and these mostly boil down to the Roman Catholic church siding with strong men who could protect the church over against the very ideals for which the church stood.
It's a good read and will make the case very persuasively.
Also, along these lines is How the Irish Saved Civilization by Thomas Cahill. There the thesis is that if it were not for the church in Ireland, we would have lost most of the learning and literature of Rome.
If you're looking to make the anti-clerical case, look to Edward Gibbon's polemic Rise and Fall of the Roman Empire. He'll make the case, but most historians agree that it is a polemic moreso than a valid historical argument.
The Middle Ages reduced innovation in the Middle Ages. If anything, the Church was the only thing keeping Western Europe literate during that time (and even then, just barely). The fact that any books from earlier times survived at all we have Church scribes to thank for.
Knowledge and the dissemination of knowledge is the lifeblood of what you would call "innovation". They were certianly repressive about a lot of things, and certianly could have been more free and open about information, but without the Catholic Church all literary activity in Europe, including the preservation of old knowledge, would have ceased completely.
The greatest destruction of knowledge caused by Christianity occurred much earlier at the start of the dark ages. The burning of the library at Alexandria and the murder of Hypatia (she was skinned alive with oyster shells) is but one famous example of the damage wrought at that time by christian mobs. These were made up of people who expected the world to end any day and who had often given away all their possessions to follow some wandering preacher. They moved across the countryside like a plague of locusts and were very destructive. As most couldn't read they burned pretty much anything written just in case it might be heretical and killed anyone who could write in case they might be a heretic or witch. The church ironically was responsible for saving much written material from these mobs as only they had the authority to turn the mobs away. While the church was mostly concerned with saving records of early church history they saved many other documents in the process.
In the middle ages the church was more interested in controlling and suppressing knowledge rather than outright destroying it. Ironically Galileo appeared towards the end of this period when knowledge was starting to escape from church control.
Hypatia was killed by order of the Church for being a scientist who dared to believe things that were contrary to Holy Scripture... and so was Giordano Bruno. In between, there were a lot of people killed and documents declared heretic.
Then there is the Index Liborum Prohibitorum - an Index of Prohibited Books - that made scientific texts like Kepeler's unavailable in Catholic countries from the creation of the printing press until well into the 18th century.
Let's look at some of the scientists banned by the Index:
So, there's some direct evidence, altho the Index is more early modern than medieval.