The Reverend Mother Gaius Helen Mohiam had no sooner arrived at Castle Caladan than she brought up the Orange Catholic Bible's commandment against thinking machines. A Reverend Mother of the Bene Gesserit — a powerful secretive all-female order — she is committed to, among other things, training and honing human talents, sifting humans from people by testing for them, and therefore preventing the enslavement of "men" by thinking machines.
As Gaius Helen Mohiam delves into aspects of this enslavement and the liberation of human minds brought about by the Butlerian Jihad, Paul Atreides drops the O.C. Bible's chief commandment:
Thou shalt not make a machine in the likeness of a man's mind.
The Reverend Mother Gaius Helen Mohiam says the O.C. Bible should have said, "Thou shalt not make a machine to counterfeit a human mind," and proceeds to ask Paul:
"Have you studied the Mentat in your service?"
This is exactly where Thufir Hawat's name comes up as Paul's reply. It turns out, that he is among the important minor characters in Dune.
Dune: Bene Gesserit's Breeding Program, Explained
The selective breeding program is run by the all-female secretive order of the Bene Gesserit, and here is what Dune says about it.
The Mentat Order
Also known as the Great Revolt against computers, thinking machines, and sentient robots, the Butlerian Jihad is a watershed event in Dune lore that began in 201 BG and ended it 108 BG. By the end of this Jihad, all thinking machines were wiped out. The ensuing commandment forbidding "the creation of machines in the likeness of a human mind" dictated the way forward. Everything from the most complex machines and eventually to the simplest computers was banned.
This explains the lack of computers in Dune, and why humans had to enhance their natural abilities. The Bene Gesserit and the Spacing Guild were established to perform similar but different functions, and the Mentat Order was created to fill the vacuum left by the lack of thinking technology. The Bene Gesserit trained primarily female students and honed their human talents. The second training school, the Spacing Guild, had a monopoly on space travel, transport, and international banking.
Thufir Hawat: Paul Atreides' Companion & Teacher on Caladan
Frank Herbert's seminal classic Dune describes the Mentats as a class of imperial citizens trained for supreme accomplishments of logic. While the description "human computers" does create a starting point to understand the Mentat Order, there's more to know about the incredible humans who have been trained to wield superior cognitive functions. Mentats are invaluable to the Great Houses, serving as political advisors thanks to their sophisticated cognitive skills.
Thufir Hawat is in service to House Atreides and is described as one of the wonderful companion-teachers of Paul Atreides. He's among the leagues of Gurney Halleck, Duncan Idaho, and Paul's parents, his mother Lady Jessica and his father Duke Leto. While every one of these characters enriched Paul in one way or another, the Mentat Master of Assassins Thufir Hawat is described as a person who:
...struck fear even into the heart of the Padishah Emperor.
Paul Atreides & Thufir Hawat's Tête-à-tête
As laid out in the beginning of Dune, Thufir Hawat served Paul's grandfather, the Old Duke, as well as his father, Duke Leto Atreides I. He has served three generations of Atreides. Now, he trains Paul in military and political strategy, espionage, and as demonstrated in their first conversation in the book, personal safety.
Paul sits with his back to a door, against Thufir Hawat's advice. His exchange with Paul anticipating their move to Arrakis gives the impression that he looks out for Paul's safety, but has less faith in his Lady Jessica, who has trained her son in the Bene Gesserit Way. He calls her and Gaius Helen Mohiam of the Bene Gesserit "witches."
Paul, who has been studying the storms on Arrakis, has a few questions about weather control, and how bad the desert planet's storms can get. Thufir Hawat tells Paul that "bad" is a cautious word for the storms that can essentially:
...eat flesh off bones and etch the bones to slivers.
Thufir Hawat says since House Atreides isn't one of the rich ones, Duke Leto cannot afford the price of satellite control that the Guild wants. He goes on to answer a few more questions about the indigenous inhabitants of Arrakis, the Fremen, and their stillsuits. Given that he is one of Duke Leto's principal advisors during this time, Thufir Hawat thinks they must move to Arrakis with caution.
Paul and Thufir Hawat's exchange also points out that the latter is a storehouse of knowledge and a vast amount of information. Not only does he present facts to Paul, but he also gives the young lad hope before their departure, despite what the Gaius Helen Mohiam has said to him about Duke Leto losing Caladan and Arrakis. After somewhat comforting Paul, Thufir Hawat bids him goodbye, as the ducal heir is to depart to Arrakis before the Mentat. He once again tells Paul to sit facing the door:
Next time we meet it'll be on the soil of your new world. Keep your knife arm free , heh ? And your shield at full charge .
To this, Paul replies:
Don't sit with your back to any doors.
Thufir Hawat is just as fascinating in Denis Villeneuve's 2021 movie adaptation as described in Herbert's Dune. He welcomes the Atreides on planet Arrakis, and as he's responsible for House Atreides' security, he assures the Duke that he's smoothing out a few rough spots. After a failed assassination attempt on Paul, he offers his resignation, but Duke Leto declines and asks him to find the spies that live among them. Thufir Hawat's story after House Harkonnen's attack and the fall of House Atreides on Arrakis remains obscure in the first movie, but he returns in Villeneuve's Dune: Part Two.