The hardware and the software. Think of a provably correct compiler.
The main relevant paragraph in this interview is the one in part 2 whose first sentence is "The catastrophic sort of error, the sort you can’t recover from, is an error in modifying your own source code."
Yes, but I don't see what relevance that paragraph has to his desire for 'determinism'. Unless he has somehow formed the impression that 'non-deterministic' means 'error-prone' or that it is impossible to formally prove correctness of non-deterministic algorithms. In fact, hardware designs are routinely proven correct (ironically, using modal logic) even though the hardware being vetted is massively non-deterministic internally.
John Baez's This Week's Finds (Week 311) [Part 1; added for convenience following Nancy Lebovitz's comment]
John Baez's This Week's Finds (Week 312)
John Baez's This Week's Finds (Week 313)
I really like Eliezer's response to John Baez's last question in Week 313 about environmentalism vs. AI risks. I think it satisfactorily deflects much of the concern that I had when I wrote The Importance of Self-Doubt.
Eliezer says
This is true as stated but ignores an important issue which is there is feedback between more mundane current events and the eventual potential extinction of the humane race. For example, the United States' involvement in Libya has a (small) influence on existential risk (I don't have an opinion as to what sort). Any impact on human society impact due to global warming has some influence on existential risk.
Eliezer's points about comparative advantage and of existential risk in principle dominating all other considerations are valid, important, and well-made, but passing from principle to practice is very murky in the complex human world that we live in.
Note also the points that I make in Friendly AI Research and Taskification.