What is Classic Style?
The Sense of Style is Steven Pinker's style guide informed by cognitive psychology and linguistics. The main idea is that the author should write in a particular mode of communication called "classic style".
The guiding metaphor of classic style is seeing the world. The writer can see something that the reader has not yet noticed, and he orients the reader’s gaze so that she can see it for herself. The purpose of writing is presentation, and its motive is disinterested truth. It succeeds when it aligns with the truth, the proof of success being clarity and simplicity.
— Clear and Simple as the Truth, Francis-Noel Thomas and Mark Turner
Here are the do's and don't of classic style:
- Eliminate meta-discourse.
Don't write "in the next section I will..."
- Eliminate "hedging".
Don't write "maybe", "it seems to me", or "I think that".
- Don't use concepts about concepts.
Don't write "approach", "assumption", "concept", "condition", "context", "framework", "issue", "level", "model", "paradigm", "perspective", "process", "role", "strategy", "tendency", "variable".
- Talk about the subject, not about research about the subject.
If you're writing about apples, then write "apples are " rather than "Dr Smith first discovered that apples are ".
Roughly speaking, Pinker recommends that the author should write about something as if neither the document nor the author nor the reader actually exists. If they're writing a book about apples, then the sentences should assert facts about apples, not about the study of apples and certainly not about the book itself.
My opinion: I like that Pinker deduces his advice from an underlying theory of communication. This is better than many style guides which present an ad-hoc list of tips. However, I think the theory is wrong. 
What's wrong with Classic Style?
I'm suspicious of "A Sense of Style" because it separates what you should write and what is true. To clarify, Pinker isn't saying there are things you should write that aren't true, but he is saying there are things that are true that you shouldn't write.
Pinker contrasts "classic style" with what he calls "postmodern style" — where the author explicitly refers to the document itself, the readers, the authors, any uncertainties, controversies, errors, etc. I think a less pejorative name for "postmodern style" would be "self-aware style". This is the predominant communication style I see on LessWrong.
In this post, I will list some defects of classic style.
Problem 1: Self-referentiality.
The Capital-T-Truth is that the book does have an author, a reader, and exists in the same world as the objects the book discusses. Therefore there are certain facts about the subject that a classic-style document won't be able to assert — namely, these are facts about the relationship between the document and the subject.
In map-territory framing: a map is "classic style" if it doesn't include a "you are here" marker. But often the map is part of the territory that is being mapped, and therefore a lack of a "you are here" marker is an omission of an important truth about the territory.
This seems defective to me. If the writers in a community assert all truths about the subject, including self-referential truths, then the community is likely to have more accurate beliefs.
Problem 2: Epistemic qualifiers.
It's very difficult to state in classic-style anything like "the probability that is " because probabilities are statements about the author's beliefs about . Recall that in classic style, the document does not know the author exists!
This is far more restricting than it may first appear. If you can't use epistemic qualifiers, then you aren't allowed to discuss anything that isn't certain. For example, if I'm writing a book about cosmology, how am I supposed to write "eternal inflation might be true"? What is that sentence about? It's not a statement about the cosmos, it's a statement about the author's knowledge of the cosmos.
This seems defective to me. If the writers in a community express their credences in their assertions, then the community is likely to have more accurate beliefs.
Problem 3: Errors should not pass silently.
In classic style, you aren't permitted to explicitly mention any errors in the document. You can't write "I might be wrong about ", or "I won't deal with in this article", etc. This is because it's the document that has errors, and in classic style, the document does not know the document exists!
This seems defective to me. If the writers in a community silence their errors, then the community is likely to have less accurate beliefs. This is because either:
- All the writers are authorities on the subject, and the opinion of non-authorities is ignored.
- Non-authorities write about the subject but the readers over-update on their assertions.
Problem 4: Incomplete information
In classic style, the author asserts their conclusions about the subject. The reader then updates their beliefs about the subject on the fact that the author has such-and-such conclusions.
The problem is that the reader is updating on incomplete information — they don't know who the author is, why they are writing the book, what evidence they have seen, and what their prior assumptions were
This seems defective to me. A community will perform better if all the writers in the community express all the information that might update the reader's beliefs.
Problem 5: Signposts
Often a document will describe itself to help the reader find information. For example "In the next section, I will do such-and-such". This tells the reader what information they will find in that section, so the reader is then better informed about whether they want to read it. But these helpful signposts aren't allowed in classic style.
This seems defective to me. If the writers in a community avoid signposts, then the community is likely to waste time reading things they didn't need to read.
Why is self-aware style better?
Here is what I would endorse: Authors should write sentences that are maximally informative to the reader. This includes sentences about the document and the author rather than just about the subject. So if you know that and you expect that the reader's beliefs about the subject would significantly change if they also knew , then write that .
Suppose an author writes "if humans encounter alien life in the next million years then the alien life will almost certainly be intelligent". Then the reader's belief about aliens is correlated with their belief about the author — what's their background? Why do they think this? Are they an economist? An astrobiologist? A UFO enthusiast? Who's testimony are they relying on? Is someone paying them to say this?
In this situation, the author is informing the reader about aliens when they answer these questions. This is the key point that Pinker misses!
My conclusion is quite strong — I think classic style is almost always socially defective in the following situations:
- Academic papers
- Non-fiction books
- Blog posts
Writing in classic style won't harm the author (and might even benefit the author) but a community where authors habitually use classic style would be worse than a community where authors use self-aware style. I can't think of any situations where the five limitations I mention would be appropriate.
Edits: various clarifying remarks.
Friendly disclaimer: Steven Pinker doesn't endorse classic style in all situations. This is Steven Pinker being moderate, rather than classic style being moderate. Also, his book The Sense of Style contains a lot of other tips other than classic style, which I've ignored in this post.