(warning: Contains spoilers, mostly high level, for the main Dune series. But frankly, if you are reading this you are probably familiar with Dune anyway. It also assumes basic familiarity with this fictional universe.)
Again and again in the Dune novels, individuals arrive at crisis situations where they must adapt to a new situation, or die. But, interestingly, humanity itself also arrives in similar situations. And those cases are presented through a consistent moral lens. "Adaptation", by connotation, is tangential to morality. When, in book 1, the emperor capitulates, it isn’t framed as a moral choice. It's simply reasonable, level-headed, self-preservation. But when humanity, as a whole, is forced to adapt, on a fundamental level, to a major change, author Frank Herbert frames it, subtly, as a permanent moral advancement. This essay is going to explore the moral progress of humanity, across the millennia covered in the Dune novels.
A Note on Canon
This essay will treat the 6 novels written by Frank Herbert (Dune, Dune Messiah, Children of Dune, God Emperor of Dune, Heretics of Dune, and Chapterhouse: Dune) as canon. The extended universe, written by Brian Herbert and Keven J. Anderson, considering its extensive deviation from the themes of the original novels, is treated as non-canon. The Dune Encyclopedia, published in 1984, is a more complex case. To avoid the snarl around it, the main arguments in this post are tuned to avoid depending on anything from the Encyclopedia, so its canonicity is unimportant.
Major Events
There are 5 events during, or referenced by, the Dune series, which cause a major change in the moral behavior of humanity. Two of them occur before the events of the first book, but are sufficiently covered, and important, that I’ll include them. The events are:
The development of atomic weapons
The Butlerian Jihad
The Kwisatz Haderach
The God Emperor, the Golden Path, and the Scattering
The Bene Gesserit grow up
I'll review each of these in turn, but first:
Immorality
To define morality, it helps to define what Herbert seemed to think immorality was, at least at a societal level. It certainly isn't brutal utilitarianism. Characters and groups throughout the series frequently make ruthless choices, based on utilitarian calculations of survival, long term benefits, etc. And those are often framed as necessary and reasonable.
In the Dune universe, societal immorality is characterized as actions that lead toward, over the long term, the degradation and extinction of the human race. The following are consistently emphasized:
Short-termism - The tendency to value immediate benefits too highly, at the expense of the long term
Conservatism - Specifically, the tendency to value security, safety, and the known too highly, at the expense of freedom, expansion, and creativity
Tribalism - Especially the willingness to significantly harm others, for comparatively minor benefits to your group
Herbert, in the first few books, contends that Dune’s humanity is doomed to a long, slow extinction, precisely because its natural tendencies in the above areas are too strong. Or it would be, if the events of the series didn't occur to avert it.
“Atomics” - A Success Story
Although atomic weapons were first developed almost 20,000 years before the events of Dune, their legacy is still important. While they endangered human survival originally, eventually society advanced enough that they are considered an insignificant risk by the time of Dune. This was mainly via significant improvements in Mutually Assured Destruction (MAD), laid out, in-universe, in "The Great Convention". The details are interesting, including additional pressure release mechanisms, and more checks and balances, that make major nuclear wars extremely unlikely. But, more interestingly for this post, this is treated in-universe as smart, moral thinking and an honest improvement in long-term human behavior, made under the pressure of a dangerous technological advancement.
The Butlerian Jihad - A Failure
On the surface, the Butlerian Jihad is seen as a grand success story. Humanity threw off the yoke of AI and was free to advance. But some people, especially the Bene Gesserit, know better. Getting rid of AI and all computers wasn't, in and of itself, an advancement of society. It was a flight from risk and a failure to address the underlying problems. In addition, the Jihad itself was so traumatizing, and the resulting restrictions so strong, that it significantly worsened humanity’s existing flaws, specifically by making humanity strongly avoid anything “new”.
In the immediate aftermath of the Jihad, there was a brief, forced, flourishing of human skills, forming the various "Great Schools", such as the Bene Gesserit, Spacing Guild, and Mentats. But after a single generation, that creativity collapsed and the whole of human civilization slid back to a medieval political structure. This was followed by 10,000 years of social and technological stagnation and slow decline.
The Kwisatz Haderach - A Disaster Opens the Way
For almost every group, the coming of a human with galaxy-encompassing prescience, who overthrows the political system, was a catastrophe. It leads to a war with the second highest death toll in history, just barely eclipsed by the Butlerian Jihad, and orders of magnitude greater than anything else. It unleashes pressures that had been pent up for millennia, in a vicious outbreak of xenophobic violence.
But that was just the surface level. The prescient effects were even worse. What the BG didn't realize, and it took a while for Paul to understand, was that prescience at this level is so powerful that it binds all of humanity as a single entity, with a single fate. No longer was it possible for an offshoot to, perhaps, survive the general fall. To borrow a particle physic analogy, there was now a universal observer, forcing the entire wave function to collapse. The degradation and extinction of humanity goes from "probably, eventually" to "definitely, soon".
Except, at the very bottom of Pandora's box, was hope. A single, narrow path out.
The God Emperor, the Golden Path, and the Scattering
With the God Emperor, we have another prescient so powerful that humanity is still bound to a single fate. But we also finally have someone far-seeing enough, and powerful enough, to force humanity along the only path out of the trap. This is cast as the most ruthless decision that a human has ever or will ever make. The “Golden Path”, as it is called, consists of two things:
To oppress humanity, so extensively and for so long, but specifically without breaking the human spirit, that the desire for freedom and expansion become so deeply ingrained that they can never be contained again. Basically, to permanently break humanity of the habit of Conservatism, as defined above.
To breed into human genetics a resistance to prescient influence. So that no future Kwisatz Haderach can ever be strong enough to bind humanity to a single destiny.
The plan works. And when it does, "all paths diverge". No single political system, or philosophy, or religion, or anything else, will ever encompass humanity again. Society, which had stagnated as "the million worlds" for millennia, will instead expand ever outward, in the "Scattering".
The Bene Gesserit Grow Up
The 5th and 6th Dune novels generally get a bad rap. For telling an incomplete story arc (Herbert died before writing the concluding 7th book), for being very weird (even by the rarefied standards of Dune), and for focusing on characters that are, somehow, even less likable than many of those in books 1-4.
In particular, the reader spends a lot more time in the heads of the BG than in any previous book. And that emphasizes just how frustrating they actually are. They have a huge list of qualities. You could make an argument that they are the morally "best" group in the universe, especially with the maturing they’ve undergone. But their flaws are so deep that even the God Emperor, back in book 4, and seeming to speak for Herbert himself, says that the BG are the only major organization that he ever considered eradicating. Precisely because their flaws are so deep and so fundamental that it wasn't clear that they could become what humanity needs them to be.
However, although books 5 and 6 don't complete a full story arc, they do complete the moral arc of the BG. For the BG, their deepest flaw is tribalism. They are deeply prideful, don't truly respect anyone outside their organization, and are constantly, intensely manipulative. They think of themselves, with better justification by the later books, as servants of humanity, leading them into a brighter future. But it is impossible to really serve, or lead, anyone when your only technique is manipulating people you don't actually respect.
In book 6, the Bene Gesserit, after 16,000 years of tribal survival, finally reach their crisis. Pressed to the breaking point, by an extermination campaign from an offshoot of their own organization, they must lead the remnants of the old imperium, humbly, or perish. Luckily a lot of prep work, some of it done long before by the God Emperor himself, pays off. They pass the test, and book 6 ends with a better humanity, with better leaders, on a brighter path.
Final Note
There are other moral lenses to view this material through, of course. A productive analysis could be done regarding how Herbert views the "Atreides honor", that appears in every book. Another could be written comparing the Dune morality with other epic franchises, for example The Lord of the Rings or A Song of Ice and Fire. But the above covers how morality develops in the Dune universe over time, and perhaps parallels some of Herbert's own thinking as the series progressed.