Charlie Stross, who has written a lot of science fiction about the Singularity (the moment at which the human race has a break with history as a consequence of tying our intelligence and consciousness to machines). Now he's written an essay called "Three arguments against the singularity," in which he discusses his personal beliefs about the likelihood of artificial intelligence, human consciousness uploading, and transcendance:
This is my take on the singularity: we're not going to see a hard take-off, or a slow take-off, or any kind of AI-mediated exponential outburst. What we're going to see is increasingly solicitous machines defining our environment -- machines that sense and respond to our needs "intelligently". But it will be the intelligence of the serving hand rather than the commanding brain, and we're only at risk of disaster if we harbour self-destructive impulses.
We may eventually see mind uploading, but there'll be a holy war to end holy wars before it becomes widespread: it will literally overturn religions. That would be a singular event, but beyond giving us an opportunity to run Nozick's experience machine thought experiment for real, I'm not sure we'd be able to make effective use of it -- our hard-wired biophilia will keep dragging us back to the real world, or to simulations indistinguishable from it.
Finally, the simulation hypothesis builds on this and suggests that if we are already living in a cyberspatial history simulation (and not a philosopher's hedonic thought experiment) we might not be able to apprehend the underlying "true" reality. In fact, the gap between here and there might be non-existent. Either way, we can't actually prove anything about it, unless the designers of the ancestor simulation have been kind enough to gift us with an afterlife as well.
(Image: How to prepare the skull for surgery, brain exposed, c. 16th century, a Creative Commons Attribution (2.0) image from brainblogger's photostream)