Dune Prequel Spoiler
“The Butlerian Jihad did it.” On a completely different note, recently re-read Dune, Messiah, and Children of Dune. With this review in mind, I do see odd characterization—superbeings who yet are variously petulant or hissing at one another—and that the prose cannot match Lessing in Shikasta. I do still enjoy the ideas and imagination Herbert brings: gypsum flats as evidence for prior water on Dune, thoughts on prescience, and the quotes that preface each chapter.
The mentat-generalist must understand that anything which we can identify as our universe is merely part of larger phenomena. But the expert looks backwards; he looks into the narrow standards of his own specialty. The generalist looks outward; he looks for living principles, knowning 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?”
— Children Of Dune, p. 221.
More on dune, from someone who goes through blogs like Leto Duncan Idahos.