I tend to think in terms I know. Evangelism is a form of marketing. You are offering a product and want to convince people to buy your product. Ethically I should not make false claims about my product or the product of my competitors. That is clear enough. Is it ethical for us to have a noncompetition agreement between us? In markets that is the one thing that economists are universally agreed is harmful to consumers. Why wouldn't that apply here -- it's been argued convincingly that the US is highly religious because competition is allowed. The religious product is better because of competition.

But what if I am offering a product that I know will change the culture and the traditions when I introduce it. Do I have a responsibility to hold back and not offer it? This is one of the questions in the wider globalization debate.

Looking back I must say I have to wonder what right we -- speaking of the west -- had for introducing Christianity in Africa and South America. What was wrong with native religions? Why not allow them to be, and to evolve as they might?

How much is this wrapped up in the old chestnut about who goes to heaven our duty to spread the word of salvation?

Others may disagree, but I'm with the camp that says that there many ways to get heaven and we can't fully understand lines in the Bible like "except by me."

As both a libertarian and a Catholic this is something I've thought about!

Somewhere between the caricatures of 'You are all going to HELL!' and 'I'm OK, you're OK' lies the truth.

One may believe the former but thank God one doesn't have to! (An underlying contentious issue 55 years ago between the Vatican and American priest Leonard Feeney, who used to preach at people on Boston Common more or less saying if they weren't registered at an RC parish they were hellbound. He was thrown out for disobedience and not his teaching, but the Roman Catholic Church said his interpretation is not what it really teaches. His underlying mistake was he taught his horrific but allowable opinion as if it were doctrine.)

Even though God became man and started the church and its sacraments of course he's unlimitable. Although God can save anybody (which would be implicitly through the church, or 'they're Catholic and don't know it' as Ronald Knox put it), conservative critics are correct that 'I'm OK, you're OK' indifferentism is a betrayal of 'except through me', 'I am the way, the truth and the life', 'there is one mediator between God and man' and so on.

(Related to this is the problem of universalism opposed to free will. Catholics can hope there are no humans in hell! But at the same time one has to accept the terrifying possibility of sending oneself there.)

So why have missionaries as more than social workers? A clue comes from the mystery writer Ellis Peters in one of the Brother Cadfael stories, The Heretic's Apprentice, in which she took on this question: she concluded that if you believe God became man and founded the church as the normal means of salvation you want to bring people closer to the possibility of salvation by bringing them into the church. Sounds good to me.

Non-competition agreements between churches don't make sense when there are churches such as the Roman Catholic (as repeated recently in the news) and Orthodox that claim to be the one true one. These agreements are hypocritical to them.

So what's fair? Persuasion, even in crude form, is free speech. Anything that doesn't involve lying about the other side or coercion (including brainwashing) - not using the state to push something against people's consciences, a policy (not doctrine) Rome came around to at Vatican II - is fine.

Andrew uses the word coercion and John makes it clear that it also includes brainwashing. I'd say it's obvious that those are unethical. The question that remains is where is the line this side of brainwashing?

Doctrinally we agree that God gave each of us free will to make choices. From the evangelism side of the coin that should mean that evangelism ought not be restrained. Except that we should also acknowledge that not everyone is capable of making such a decision. Is it ethical to offer them the benefits of salvation?

One last thought. Aren't most of us uncomfortable with the similarities between us 100 years ago and the fervor of the South Korean missionaries in Afghanistan and elsewhere?