Ray is one of my heroes. I tend towards cautiously thinking he is probably correct. He is at least correct enough that we should try to create the minds as he says and see where that leads us. The journey will teach us a lot even though I don't think the destination will be where we think.
There are some big research hurdles to even contemplate what Ray is proposing though. We're only just starting to work with AI that feeds back into itself (e.g. RNNs) previously our neural networks were sense-responses machine that worked in one direction only. And, we have engineering problems dealing with things at the scales needed to pull off Ray's brain simulation. But yeah, let's give it a shot.