Thus, in all their intellectual activity, scholars are accustomed to dealing with matters of the mind and with thoughts. They do not know anything else. Politicians, on the other hand, must pay attention to the facts of the outside world and the conditions attaching to and depending on (politics). (These facts and conditions) are obscure. They may contain some (element) making it impossible to refer them to something like and similar, or contradicting the universal (idea) to which one would like them to conform. The conditions existing in civilization cannot (always) be compared with each other. They may be alike in one respect, but they may differ in other respects.
(Now,) scholars are accustomed to generalizations and analogical conclusions. When they look at politics, they press (their observations) into the mold of their views and their way of making deductions. Thus, they commit many errors, or (at least) they cannot be trusted (not to commit errors). The intelligent and alert (segment) of civilized people falls into the same category as (scholars). Their penetrating minds drive them toward a searching occupation with ideas, analogy,and comparison, as is the case with jurists. Thus, they (too) commit errors.
The average person of a healthy disposition and a mediocre intelligence has not got the mind for (such speculation) and does not think of it. Therefore, he restricts himself to considering every matter as it is, and to judging every kind of situation and every type of individual by its particular (circumstances). His judgment is not infected with analogy and generalization. Most of his speculation stops at matters perceivable by the senses, and he does not go beyond them in his mind, like a swimmer who stays in the water near the shore, as the poet says:
Do not go out too deep when swimming. Safety lies near the shore.
Such a man, therefore, can be trusted when he reflects upon his political activities. He has the right outlook in dealing with his fellow men.--Ibn Khaldun "Scholars are, of all people, those least familiar with the ways of politics," The Muqaddimah translated by F. Rosenthal.
In context, Ibn Khaldun a "scholar" is a smart-ist, applied Aristotelian philosopher/social scientist. Before I get to his explicit charges it is worth noting that his critique(s) of the experts is not a plea for better or different expert rule. He is, thus, not offering an alternative expert or smarts to the problem of expertise. He is, in fact, quite explicit that he is looking for average minds. This is because he thinks that smart minds just have incurable vices qua the needs of political rule and political life. For smart people have a species of experts overconfidence, that is, a tendency toward excessive abstraction and generality and make the data conform to their models and principled commitments (that is, he also diagnoses a certain kind of fixity of mind).
So, Ibn Khaldun anticipates (the Machiavellian) Spinoza in his critique of philosophers:
For they conceive of men, not as they are, but as they themselves would like them to be. Whence it has come to pass that, instead of ethics, they have generally written satire, and that they have never conceived a theory of politics, which could be turned to use... Accordingly, as in all sciences, which have a useful application, so especially in that of politics, theory is supposed to be at variance with practice; and no men are esteemed less fit to direct public affairs than theorists or philosophers.--Spinoza, Political Treatise.
The Spinozist critique is designed to promote an alternative, more suitable sort of expertise (one that draw on a sufficiently sober image of human nature and with the help of Spinozistic theory of the passions and anthropology, Spinozistic political science can draw proper causal and general inferences that are useful to political life). Now, I am not suggesting Spinoza is still promoting philosopher-kings. But I claim that he does argue that Spinozistic political science can inform political rule.
By contrast, Ibn Khaldun rejects not just the very idea of philosopher kings, but also the role of political science and smarts in politics. It's a distraction and dangerous. Rather, what's required in political rule/life according to Ibn Khaldun is (a) emotional intelligence ("dealing with his fellow men"), which is crucial because political authority relies upon and promotes group feeling/cohesion against internal and external sources of instability (for Ibn Khaldun the international area is zero-sum and in permanent conflict); (b) a willingness to engage and stick with contextual judgments of situations because political life is according to him intrinsically a matter of judgment of particualrs, and (c) a respect for existing traditions and practices that are familiar to the citizens, which fits his psychological and socialiological emphasis on the significance of habits in social and political life.
As an aside, it's not that Ibn Khaldun is intrinsically hostile to experts and sciences/philosophy. (He some reservations about some kinds of metaphysics in light of revelation, but about that some other time.) In fact, he expects the development of the sciences, including political sciences, it to be a natural byproduct wealth, extensive division of labor, and city-life. For, anticipating Adam Smith, in wealthy, cosmopolitan cities with extensive markets the crafts and technologies will thrive, and the atmosphere will be hospitable to the sciences.
As my students pointed out to me, the effect of (a-c) is conservative, there is a built-in-bias against innovation. In addition to commitment to justice and norms of good governance (recall), good political leadership tends to stick to the tried and true on this account. At the start of his book (recall), Ibn Khaldun recognizes that a society's ideology or civil religion; provides a shared understanding of and guidance to the political world a society has inherited from the past. While it is not, in principle, incompatible with the truth, it does not aim at it (and so need not be truthful); he is quite clear that this ideology never grasps the hidden causes of political life.
So, one way to understand Ibn Khaldun's analysis of political rule is that it needs to exercises by those that feel comfortable and accepting of the traditions they have inherited. Some other time I discuss the more radical strains in Ibn Khaldun's thought (and also how he understands [recall] his own political science, which does track hidden causes], but here I just want to dispel the idea that the ideal (not so smart) ruler of Ibn Khaldun has a slavish respect for the status quo. For, by making room for the significance of contextual judgments, he also thinks good political rule can generate considerable innovation without stubborn adherence to the past or principle. It is probably too anachronistic to suggest that Ibn Khaldun is a theorist of what has come to be known as spontaneous order who is quite clear on the material and cultural conditions that structure social life, but he is a theorist of spontaneous order without the trappings of natural law theory or a commitment to human progress.