Zero,
I wanted to get you a link to d'holbach's Priests, an article in The Encyclopedie compiled by Diderot, but I needed to pay for the privilege, so I will quote from it instead.
You choose to put Christianity to one side, fine. This puts you far enough back to the times of religious inspired human sacrifice.
[Priests] made men tremble for fear of the punishments with which the angry gods menaced rash people who would dare their mission or discuss their doctrine. To establish their empire more securely they painted the gods as cruel, vindictive, and implacable…Then human blood flowed with great torrents on the altars; the people, subjugated by fear and intoxicated with superstition, believed they could never pay too dearly for celestial benevolence. Mothers delivered with dry eyes their tender children to the devouring flames. People submitted to a multitude of frivolous and revolting practices that were, however, useful to the priests, and the most absurd of superstitions extended and consolidated their [the priests] power.
D'holbach didn't need to personalize it so much, he could have replaced 'the priests' with 'priesthood' or even 'religion', but I think he makes a good point. And what he describes is to be found in mesopotamia, egypt, america, everywhere in the ancient world.
Did these religions tend to serve the causes of humanity? Hardly. What about the cause of science or human knowledge per se? After all, the priests were educated, and the educated were virtually all priests. D'holbach continues
Free from cares, and assured of their empire, these priests, with a view to charming away the boredom of their solitude, studied the secrets of nature, mysteries unknown to the average man; hence the highly praised knowledge of Egyptian priests…medicine has been practiced by the same men. The priest's usefulness to the people was bound to consolidate their power…The study of physics: furnished the means to strike the imagination with dazzling works. People considered them supernatural because they were ignorant of the causes…Astonished human beings believed that their sacrificial priests controlled the elements…and commanded favours from heaven.
I think he goes too far in what he says, but I agree in so far as saying religion has broadly locked up scholarship and all new knowledge for its own reasons. It still would if it had any, that came to an end in the 18th Century, imo, hence my use of D'holbach.
Philo
"It is an absurdity to believe that the Deity has human passions, and one of the lowest of human passions, a restless appetite for applause." [David Hume]