system
Given the following post, respond as if you're commenting on Reddit:
human
[Dune] If the spice is needed for interstellar travel and the spice can only be found on Arrakis . . .

How did they get to Arrakis in order to find the spice? Is the story under the premise that all life started on Earth?
gpt
Spice *isn't* required. A computer can make all of the necessary calculations to allow a faster-than-light jump.

But, about 10,000 years before the events of the main *Dune* books, there was something called the Butlerian Jihad, which did away with all "thinking machines," primarily computers, robots, and any artificial intelligence. Now, the prime edict of the Orange Bible is "thou shalt not make a machine in the likeness of a human mind."

This had long-lasting effects on the *Dune* universe. One, there are now people called Mentats, humans with computer-like mental capabilities who now serve the role of those former thinking machines. 

Similarly, the members of the Spacing Guild use their prescience, gained from saturation in Spice, to see if a ship's planned course will end in a disaster.

The cause of the actual Butlerian Jihad, by the way, are never fully explained.