This thoughtful article comes from Dr. David J. Linden, who takes up the singularity debate — posted at Ray Kurzweil’s own website, KurzweilAI.net. Here’s a snippet:

As much as I respect Ray Kurzweil and appreciate his willingness to make predictions about and argue for specific future events, I take issue with his timetables for both the introduction of brain-nanobots and the ability to upload the contents and meaning of a brain.

I am a neurobiologist and I have spent the past 28 years engaged in studies of the cellular and molecular basis of memory and cognition. I am an optimist and a technophile, but I believe that I speak for the vast majority of brain researchers when I express serious doubts about Kurzweil’s timetable

via The Singularity is Far: A Neuroscientist’s View | KurzweilAI.