This statement is the primary commandment of the Great Convention in the universe of Dune (written by Frank Herbert). It is not only a civil law, but also a religious commandment, featured in the Orange Catholic Bible.
The Great Convention stemmed from the Butlerian Jihad, humanity's final battle against machines possessing artificial intelligence. To prevent this abomination from happening again, the surviving humans founded a government and several religions enforcing this sacred mandate.
As a compensation for the loss of machines to process data, humanity began to develop mental talents and formed the Great Schools.
- Mentats - humans who have developed their abilities in calculation and analysis.
- Bene Gesserit - Masters of their bodies (the prana-bindu discipline), genetics, and politics.
- Spacing Guild (often just the Guild) - Beings who possess some manner of prescience, generally used to pilot spaceships through foldspace.
Of course, all of these schools require the use of
melange to exercise their full abilities.
Oddly enough, the most fanatical defenders of the prohibition against thinking machines is the Tleilaxu race, which can barely be called human.