In the 2010 Boréal conference Ted Chiang had an interesting take on the singularity and the computable brain. There is a transcript (in french) here : http://www.actusf.com/spip/article-9802.html.
To sum it up that is what he says : "There is this thing called ethnobiology, a sub-dicscipline of anthropology, that studies the way civilizations understand and represent the living things. Ethnobiology reveals a constant in History : we tend to compare our brain to the most complex technology we know. At the Renaissance, philosopher assimilated the brain to a very complex and subtle clockwork, Freud compared it to a steam engine, which pressure should be evacuated to avoid explosion. In the 40's, schoolboy and schoolgirls were told that brain was like a telephone exchange. Today, computers are the most advanced technology we know, so we tend to compare our brain to it. But like our predecessors, it's very likely that we are wrong. Let just think forward, and admit that we are totally biased by the fact that computer are now inherent part of our life. Let's admit that there is a chance that our brain may never be modeled by a computer."