Mentat be thy name

First law of Mentat: A process cannot be understood by stopping it.

Understanding must move with the flow of the process, must join it and flow with it.
Frank Herbert, Dune


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Above all else, the mentat must be a generalist, not a specialist. It is wise to have decisions of great moment monitored by generalists. Experts and specialists lead you quickly into chaos. They are a source of useless nit-picking, the ferocious quibble over a comma.

The mentat-generalist, on the other hand, should bring to decision-making a healthy common sense. He must not cut himself off from the broad sweep of what is happening in his universe. He must remain capable of saying: "There's no real mystery about this at the moment. This is what we want now. It may prove wrong later, but we'll correct that when we come to it."

The mentat-generalist must understand that anything which we can identify as our universe is merely a part of larger phenomena. But the expert looks backward; he looks into the narrow standards of his own specialty. The generalist looks outward; he looks for living principles, knowing full well that such principles change, that they develop.

It is to the characteristics of change itself that the mentat-generalist must look. There can be no permanent catalogue of such change, no handbook or manual. You must look at it with as few preconceptions as possible, asking yourself: "Now what is this thing doing?"
The Mentat Handbook, Frank Herbert, Children of Dune

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A Mentat's real skill lay in that mental construct they called "the great synthesis." It required a patience that non-Mentats did not even imagine possible.

Mentat schools defined it as perseverance. You were a primitive tracker, able to read miniscule signs, tiny disturbances in the environment, and follow where these led.

At the same time, you remained open to broad motions all around and within. This produced naivete, the basic Mentat posture, akin to that of Truthsayers, but far more sweeping.
Frank Herbert, Chapterhouse: Dune