Sighkey made a very interesting point about cathedrals, to wit:
 
“One should remember that the price of those beautiful cathedrals were lives lost  and also thousands of pounds of money which could have been better put to use helping those who were starving and/or dying of the numerous diseases that were floating around at the time. http://www.bbc.co.uk/history/lj/churchlj/cathedral_08.shtml
 
I have to admit that my initial reaction was, “It was worth it.”
 
Before you recoil in horror, consider the analogous case of the automobile.
 
Cars are a major killer in the U.S., way ahead of AIDS and terrorists and other bad things, but most of us would agree that their benefits outweigh their dangers.
 
But the cost/benefit ratio of cars can be calculated more easily than cathedrals. You can estimate the number of deaths and injuries and compare it to the number of people who were able to get medical care because they had a car or ambulance to hand. Admittedly, this is artificial, since it leaves out all environmental questions and also all non-medical quality-of-life questions, but it does give you an apples-to-apples comparison.
 
Cathedrals are harder.
 
For one thing, there isn’t a direct way to compare the harm of cathedrals — dangerous working conditions and opportunity cost — with the benefits, assuming those benefits to be things like increased joy.
 
Let’s try anyway. First, consider the economic issue: could the money spent on cathedrals be better spent on feeding the poor?
 
Actually, since a cathedral town was more economically stable than other towns and had tourist income, there might have been a net advantage. The cost of a cathedral also got spread around — it wasn’t like an obscene salary for a baseball player. The money would have gone to workers, people who prepared the raw materials, and so on.
 
There also is the question of how the money would otherwise have been used. When I read recently in the Wall Street Journal that khaki trousers could now be bought for $500 to $1000 a pair, I immediately thought of how many starving children could be fed for that amount of money. However, the kind of guy who plunks down $800 for his pants does not — if someone came up and said, “Hey, dude, you know how many orphans could be fed for that many ducats?” — turn around and donate the funds to the local soup kitchen instead. He’d just buy golf clubs. Equally, the people (and it seems to have been largely individual donations that funded cathedrals) who put up the money were not likely to have spent it for alms if they hadn’t given to the cathedral.
 
Nor, when it comes to diseases, would money have helped. It would have helped a lot if someone had thought, “Let’s use the money for the cathedral to build sanitary septic systems instead!” but that wasn’t going to happen. A lack of information would keep the lack of money from being an issue.
 
What about the lives lost? I don’t know whether cathedral work was particularly dangerous in the way that, say, mining has always been. But people in those days died routinely from sepsis, childbirth, food poisoning, random violence, etc. My plan is to die comfortably in my sleep at the end of a long and happy life, but if I had to choose between dying in the production of a cathedral or from random medieval violence, I’d go with the cathedral.
 
Still, there are the costs. What about the benefits? Cathedrals were the center of the towns, often providing education for children, rest for travelers, sanctuary for the endangered, food for the indigent, and legal services as well as all religious care. They were the place for christenings, weddings, and funerals. They were, as I have already mentioned, one of the very few places where ordinary people could experience the arts, or even spend time in a relatively comfortable place.
 
And of course we are doing an omniscient, omnipresent balance sheet. We make a total on the left side of the dangers and opportunity costs for the two hundred years of building a great cathedral. On the right, we stack up the benefits of that building: steady work for generations, the satisfaction of craftsmanship, the belief of the donors that their monetary gifts would help them to salvation (which presumably salved their consciences and reduced stress), the income for the town as pilgrims arrived, the important charitable work of monks housed there, the great works of art — including music — prepared for the cathedral, itself a work of art.
 
Then we have to total up the benefits since the building was completed. Continued work, of course, since upkeep is constant and the buildings are still in use, and continued works of art. The pleasure of all visitors since that time, the moments of calm in lives that may have been difficult for many reasons. Isn’t the right side of the balance sheet getting a taller stack than the left?
 
At the very least, I have greatly enjoyed thinking about this. Thanks, Sighkey!