"truth in both sides" is indeed the right way to approach most controversies. And discussions should always be carried out in a polite and good-tempered way.

But there are issues where the evidence has added up to a conclusion. The sun doesn't go round the earth. Smoking causes cancer. The Holocaust happened.

That doesn't mean it may not be possible for people to honestly hold contrary opinions, on the basis of distorted facts put out by people with particular undiclosed agendas.

It seems to me that the case that our industrial society is making a serious contribution towards global warming that is liable to have devastating effects is an example of something that now has to be treated as fact rather than speculation.

That doesn't rule out that there are other factors in play, and that some degree of global warming may well have causes beyond our control - but if sop it seems pretty obvious that this merely makes it more important that we don't go on mamking a threatening situation even worse.

When you are in a hole, you stop digging. Even if it's a natural hole.