"a safe AI design is possible and simple"

Excuse me, but of course it is. To believe that it's neither possible nor simple is to believe that human minds are so needlessly complex, viewed from the outside, that bottling up our model-forming and evaluation-forming processes for artificial processing is impossible or intractable.

The problem only looks hard because people are applying the wrong maps. They come at it with maps based on pure logic, microeconomic utility theory, and a priori moral philosophizing, when they really need the maps of statistical learning theory, computational cognitive science, and evaluative psychology.

Sometimes when things look really improbable, it's because you've got a very biased prior.