I'm going to say from the start that what I write next is speculative. I am writing my thoughts and feelings, not raw data. I admit that I could be wrong about everything that follows. It happens, especially on nights like this when I should have been asleep an hour ago.

As an Extropian I have a lot of hope for nanotech. It certainly has potential even if most of Drexler's predictions about it fail to come true. Once the novelty of it wears off and people quit using it to make microscopic violins and wine glasses, we might actually see some progress. I doubt that we will ever see Assemblers or utility fog, but it won't hurt to keep our fingers crossed. While the gray goo threat seems to be a will-o'-wisp, there is still opportunity for destructive applications.

What effect it might have on religion is difficult to guess at. A lot would depend on what can actually be done with the technology. Assuming that Drexler's speculation of life extension comes true, I would imagine that it would be met with outright hostility. Staying true to hypocritical form, the neo-Luddite zealots would probably capitalize on some benefits of the technology while lambasting the life extension application. Consider how todays fanatics reap the life extending reward of modern medicine by frequenting physicians offices while decrying gene therapy and stem cell research.

Also remember that science pushes religion into the dark corners. Invoking the god of the gaps is their reactionary defense at the moment. They react this way out of fear. These people fear death, and when science deprives them of huge chunks of their comforting delusion, they become increasingly unstable. There is a possibility of invoking a violent response to science if we push them too far into those corners. Cornered animals are unpredictable, but an all out attack is always something to watch out for. Worst case scenario would be burning of universities and people rounded up in concentration camps for failing to follow some charismatic religious leader's interpretation of scripture. Think 1940's Germany and Dark Age Europe rolled together in one big fanatical orgy of destruction.

Best case scenario would be a mass enlightenment, with theists everywhere waking up and realizing that with the promise of a greatly extended life, they no longer needed the superstition of their illiterate goat herding ancestors.

In both cases, we are probably talking science fiction, as it doesn't seem likely that nanotechnology will make such huge advances in damage repair. Lesser medical advances, say using nanobots to unclog arteries, would probably not have any noticeable effect on religion. Fundies are opposed to biology. As long as they perceive nanotech as mechanical, they will ignore it until such a time that it begins to threaten their delusions.

When I hear the term " playing god ", I always chuckle. We created god, so we might as well play god.