When is it appropriate to use \paragraph?

Question

LaTeX provides seven sectioning commands:

1. \part
2. \chapter
3. \section
4. \subsection
5. \subsubsection
6. \paragraph
7. \subparagraph.

For most of the documents I write or come across, \subsubsection seems to be the deepest sectioning level used. Then there's the "rule" (by Tufte perhaps? I am unable to find the source right now) that suggests that the document outline should not be deeper than three levels, which would leave me somewhere between \subsection and \subsubsection depending on the document class being used. At any rate, I have not yet come across a use case for \paragraph and, thinking about it, I realize I don't know when it would be appropriate to use it. So, that's my question: when, if ever, should \paragraph be used?

Answer 1

I learned in elementary school that a document should not be divided more than the intellectual content deserves. The rule is often breached, especially by lawyers. One reason for numbering down to eight or nine levels is that it is easy for us lawyers to refer to item 2.1.1.2.3.(i)(b)(V)(A) in a complicated legal text, making the text even harder to read and interpret. Then we lawyers are sure you have to visit a lawyer and pay him to help you with the interpretation.

Bringhurst (The Elements of Typographic Style) suggests three levels.

(And: I am a lawyer myself)

Answer 2

There is no real need for that many subdivisions unless (perhaps) you are writing a twenty-volume comprehensive book and you use continuous numbering of sections.

While Bringhurst's three levels may be too little for the average academic book (i.e., 300 to 600 pages, with very structured content unlike in literature), you won't see many that have over five levels of headings either. Five levels means \part, \chapter, \section \subsection and \subsubsection, and that's the most you will usually find.

But I would like to suggest that \paragraph and friends can be used a bit differently from \section commands, from a semantic point of view. It is common practice to define paragraphs as inline headings, and to hide them from the table of content. Say you wanted a book with two main headings (\chapter and \section) and a third heading that creates a small break in the text but doesn't use a full line, then \paragraph would be appropriate.

What I really mean is that the headings are not there for you to use each and every one of them as if they formed a rigid hierarchy, but because they have different meanings. A \chapter starts a new page, a \section does not and a \paragraph has yet another style. You don't have to exhaust \subsection and \subsubsection before jumping to \paragraph – the \sub… are always pretty much optional. It is better to use them in a semantic way.

Unless you are a lawyer of course, as mentioned by Sveinung.

Answer 3

Funny as I found Sveinung's answer, I can't resist leaping to the defence of my profession (and without payment!).

It's a mistake to see these divisions as forming a continuous sequence. Division into, say, parts and chapters is really discontinuous with division into sections and so forth within a chapter. Paragraph headings, as ienissei points out serve a different purpose again. In a long text that will be consulted rather than read continuously they help one to scan for the relevant part. That I think gives a good guide to when they are appropriate: in works of reference, mostly intended for an audience that will probably be reading fast with a particular objective, and which will have a general idea already about the sort of information the text will contain. Reference manuals for professionals, basically.

The endless subdivisions of lawyers in formal texts are different again: they don't structure the document, but split up individual paragraphs and sentences of often very dense material in a way that helps clarify it and facilitates cross references. This sequence is again separate from and discontinuous with the headings and subheadings which are about the structure of the document.

Believe it or not, they actually help, though like headings they can be overdone. Anyone who has struggled through an old legal document in which there is no punctuation because it was believed that said punctuation might rather than assisting the reader lead to misinterpretation of the text and accordingly to misapplication of the same will be likely to appreciate the advantages of the modern style its inelegance notwithstanding. !