Stanford historian on the singularity

Currently, we don't have basic tech for scanning, nor even anything on obvious track (for having both precision and volume speed). Present simulation methods are still in their infancy. From general considerations of technological progress, we can expect that to change eventually, especially if nanotech takes off (for scanning, not simulation). Give it 20-50 years for when tech catches up, and another 10-30 years for reliable simulation of short-term dynamics. Then comes another difficulty: we need to support all brain reconfiguration processes to enable long-term cognition. And then, we need to comfortably graft this with environment, which is probably a little more difficult than writing engines for computer games. Give it 10-20 more years. When the thing starts working, long-term cognitive problems will probably come up and won't be debugged for some years to come. Overall, (20-50 fixed)+(30-60 development) years, and accounting for planning fallacy and difficulties with making this into a reliable development process (such as funding), say factor of 2, more like 80-170. The hypothesized source of delay is from organizational, engineering and software development difficulties, not inadequacy of technological infrastructure.