>>26195>Technically speaking a calculator doing simple arithmetic is still doing thinking for you.
Yes, correct. They don't have calculators in the Dune universe. That's at least partially the role of the mentats.
I know that lots of computers are basically calculators, but (at least in Frank Herbert's original novels) the Butlerian Jihad was more of a philosophical restriction on computers based around the idea that humanity was becoming too intellectually dependent on them, and this dependence was preventing humanity from reaching its full potential. A potential realized in the likes of the mentats, navigators, and Bene Gesserit.
However, a lot of their technology is clearly computerized and it would have to be. I've always interpreted this to mean that they have some basic "dumb" computerization that neither has artificial intelligence of any kind nor performs any function that could be viewed as "thinking for humans".
So, for instance, the hunter-seeker is clearly a device that would require extensive computerization to function, but still requires a human pilot.
Also, there's a lot of spiritual and religious themes in the books, and one of the impressions I got was that the people of the Dune universe regard thought and consciousness as something sacred, and consequently not something to be given over to machines.