A learning strategy for history or literature: Subjective judgment is important; careful reasoning is not.
Really, careful reasoning is not required? This is patently false, and probably based on his English and History experiences in high school decades ago. I find that people who say such things rarely have adequate exposure to the subject area. Someone I encounter on a daily basis actually in the CS research community.
If you're not using deductive reasoning in the study of history or literature you're doing something horribly wrong. The authors statement is flat out wrong, no matter how you spin it.
But he isn't presenting some random opinion, he's claiming he's teaching how think clearly and one assumes he's trying to present well by example. Well, strike-three.
-- I think contrary to his rules, I don't think there is any set, global rules for presentation beyond the basic language skills he correctly says are rather in-born. What there are is a series of interlocking conventions and strategies on a per-subject and per-topic basis. Learning those well takes a long time and can't be summarized by a how-to...