ibn khaldun notices regression to the mean (and entropy)

too bad he didn’t get his behavioral genetics right, though. but that’s ok. he was ahead of the times. from The Muqaddimah: An Introduction to History; In Three Volumes – I [pgs. 105-106]:

“14. Prestige lasts at best four generations in one lineage

“The world of the elements and all it contains comes into being and decays. Minerals, plants, all the animals including man, and the other created things come into being and decay, as one can see with one’s own eyes. The same applies to the conditions that affect created things, and especially the conditions that affect man. Sciences grow up and then are wiped out. The same applies to crafts, and to similar things.

“Prestige is an accident that affects human beings. It comes into being and decays inevitably. No human being exists who possesses an unbroken pedigree of nobility from Adam down to himself. The only exception was made in the case of the Prophet, as a special act of divine grace to him, and as a measure designed to safeguard his true character.

“Nobility originates in the state of being outside. That is, being outside of leadership and nobility and being in a base, humble station, devoid of prestige. This means that all nobility and prestige is preceded by the non-existence of nobility and prestige, as is the case with every created thing.

It reaches its end in a single family within four successive generations. This is as follows: The builder of the family’s glory know what it cost him to do the work, and he keeps the qualities that created his glory and made it last. The son who comes after him had personal contact with his father and thus learned those things from him. However, he is inferior to him in this respect, inasmuch as a person who learns things through study is inferior to a person who knows them from practical application. The third generation must be content with imitation and, in particular, with reliance upon tradition. This member is inferior to him of the second generation, inasmuch as a person who relies upon tradition is inferior to a person who exercises independent judgement.

The fourth generation, then, is inferior to the preceding ones in every respect. Its member has lost the qualities that preserved the edifice of its glory. He despises (those qualities). He imagines that the edifice was not built through application and effort. He thinks that it was something due his people from the very beginning by virtue of the mere fact of their descent, and not something that resulted from group (effort) and (individual) qualities. For he sees the great respect in which he is held by the people, but he does not know how that respect originated and what the reason for it was. He imagnes that it is due to his descent and nothing else. He keeps away from those in whose group feelings he shares, thinking that he is better than they. He trusts that (they will obey him because) he was brought up to take their obedience for granted, and he does not knw the qualities that made obedience necessary. Such qualities are humility (in dealing) with (such men) and respect for their feelings. Therefore, he considers them despicable, and they, in turn, revolt against him and despise him. They transfer leadership from him and his direct lineage to some other related branch, in obedience to their group feeling, after they have convinced themselves that the qualities of the (new leader) are satisfactory to them. His family then grows, whereas the family of the original (leader) decays and the edifice of his ‘house’ collapses.

“That is the case with rulers who have royal authority. It also is the case with all the ‘houses’ of tribes, of amirs, and of everybody else who shares in a group feeling, and then also with the ‘houses’ among the urban population. When one ‘house’ goes down, another one rises in another group of the same descent.

The rule of four (generations) with respect to prestige usually holds true. It may happen that a ‘house’ is wiped out, disappears, and collapses in fewer than four, or it may continue unto the fifth and sixth generations, though in a state of decline and decay. The four generations can be defined as the builder, the one who has personal contact with the builder, the one who relies on tradition, and the destroyer.”

(note: comments do not require an email. asabiyyah.)


  1. That’s why stumbling upon the idea of a hereditary constitutional monarchy is so wonderful. The prestige comes by habit and custome, rather than needing to be built up every four generations. That’s a good thing because the building up so often requires slaughtering people in huge numbers.


  2. “Prestige is an accident that affects human beings.”
    “Sciences grow up and then are wiped out. The same applies to crafts, and to similar things.”
    Very Islamic. Allah is a god of the random, unlike the other Abrahamic religions, which place God as order, Allah is a god of discord. Of course for a Muslim there would be no order in Science, since there is no order. Also, the traits for Muslims in those times were probably far different.

    Since Muslim men took whomever they wished for their wives, there was no sort of breeding program like that of Europe…Where the classes differed (even though people of course still moved up and down), as well as all the other resources making it different stated on this site. A Muslim man could have his pick of any four, or in the case of these men, MORE women. When you force the power of breeding like this, a FEW men will gather MANY women, many of these women will force these men’s next generations closer down to the mean. Nor, since there was no aim for the education/betterment of women, there was no clear definable way to know intelligence from not (assumption). Of course one could still look at the other family members. HOWEVER, I am guessing a Muslim man’s offspring were all his inheritors, while in Europe, bastard children never had that privilege. Bastard children returning to the mean was good for the general population, since they were commoners like everyone else, while the many offspring of a Muslim man forced all of his future generations to be subpar (since there were no limits and no benefits to marrying on par or ABOVE your station since you could have more then one wife). Take Clark: he notes in Europe it wasn’t uncommon for men to take the names of their wives if they came from better positions. In Islamic countries I cannot ever imagine women having any power like this to THAT extent (even though I am sure they had some class system, and some womanly power, just FAR FAR from the extent as Europe).

    Of course, these are all theories. But the fact is: in most cases what Ibn says ISN’T true. We also know that in Islamic countries it is actually the Christians who are the upper class since the Islamic system creates under classes of Muslims (again Clark also talks about this in terms of the Copts). With this, we can assume that Ibn was just observing, and generalising about his time and era, and what is effectively a greater pattern in the Islamic world.
    WITH THAT SAID, he does have a major point: even now, look at your extended family, and you can tell who is going UP and who is going DOWN (in a loose sense) just by simply looking at who they married (and where that person came from). Spawn with someone who is at your level or slightly higher if you want children like yourself.

    TLDR: Muslims have a shitty social structures, this is what Ibn sees. By continually marrying many, important Muslims return to the mean much more rapidly. They ‘scatter’ genes instead of ‘concentrate’.


  3. Of course this theory of generational decline by Ibn Khaldun is not very like a modern view of ‘regression to the mean’ at all.

    We think of regression to the mean as an effect of a random genetic element whereas Khaldun only mentions environmental effects. He attributes the success of the first generation to unknown factors but the decline of the second generation he attributes to inferior teaching. This is just flat out wrong. The evidence doesn’t support this pattern.

    Genius does indeed emerge from time to time but Mozart’s father or Mills’ father – try as they might – couldn’t establish genius as a permanent feature in their respective family lines. Ibn Khaldun’s thesis only seems impressive if you know no history.

    If this sort of thinking is common in Islam – no wonder they have failed to advance. In the 14th century in the West – a very, very bad time for Europeans- the church and the government were quite concerned about genetics and family lines. They would have rejected this bizarre account of world history. They would have rejected the notion that eminence arises spontaneously and fades due to poor transmission through poor teaching.

    I suppose I should revere this famous Muslim but I’m afraid he strikes me as just a crackpot.


  4. It sounds exactly like the “rags to rags in three generations” saying that is commonplace when talking about family corporate dynasties in the West. It sounds less crackpot to me, more like stating the bleeding obvious.


  5. Great find – seems like wise individuals have been noticing regression to the mean and trying to guess at the causes for a while.

    Random shuffling of genes will naturally throw up outliers with each generation. By definition the offspring of those outliers will regress to the mean unless outliers only marry other outliers such that their offspring regress to a new outlier mean. If they can keep up it up over generations a caste of outliers could be maintained for generations at a cost of lots of genetic defects gradually building up over time.


  6. @patrick – “Of course this theory of generational decline by Ibn Khaldun is not very like a modern view of ‘regression to the mean’ at all. We think of regression to the mean as an effect of a random genetic element whereas Khaldun only mentions environmental effects.”

    yes. that’s why i said it was too bad he didn’t get the behavioral genetics right. (~_^) and also why i said he “noticed” it. he didn’t manage to explain it, tho.


  7. @grey – “…seems like wise individuals have been noticing regression to the mean and trying to guess at the causes for a while.”

    yes, i think so, too!


  8. Simon, I heard it as “Clogs to clogs in 3 generations”. I am amazed HBD hasn’t flagged it.


  9. Or from Aristotle, 17 centuries earlier:

    Being well-born, which means coming of a fine stock, must be distinguished from nobility, which means being true to the family nature — a quality not usually found in the well-born, most of whom are poor creatures. In the generations of men as in the fruits of the earth, there is a varying yield; now and then, where the stock is good, exceptional men are produced for a while, and then decadence sets in. A clever stock will degenerate towards the insane type of character, like the descendants of Alcibiades or of the elder Dionysius; a steady stock towards the fatuous and torpid type, like the descendants of Cimon, Pericles, and Socrates. (Rhetoric, Book II, Chapter 15)


  10. Anecdote: I was taught by my parents that rising from one social class to another takes three generation — divided US population had 10 vertical classes, they said. They also told me that downward mobility was much easier than upward, and could be accomplished in one generation.


  11. But is it true? It is in my family to an extent but the Bernoullis kept a high run rate for generations. The present Faraday still invents significant stuff. Distilleries like his ancestors The Cecil’s are still not far from power. 400 years and counting.


  12. “But is it true?”

    I think it’s true on average but as it’s based on probability there are likely to be exceptions.


  13. The Cecil’s explicity bred themselves for intelligence rather then marrying heiresses for the land they owned.


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