If abstract is a sample of about-ness, then a table of contents is sample if is-ness. Some have said that journal articles should not have table of contents (instructional staff at the UNT program teaching the Metadata I course). I disagree, but so does Habing, et al (2001). Sometimes more than an abstract a table of contents can deliver a substantial understanding of what an article is and is about by displaying its structure. In fact many law review articles actually include a table of contents prior to the main part of the article. Law review articles can be over 70 pages in length. An outline offers useful information to the potential reader.
An example of an outline from a linguistics article.
Roberts, David. 2011. “A Tone Orthography Typology.” Written Language & Literacy 14 (1): 82–108. doi:10.1075/wll.14.1.05rob.
- The six parameters
2.1 First parameter: Domain
2.2 Second parameter: Target
2.2.4 Dual strategies
2.3 Third parameter: Symbol
2.3.1 Phonographic representations
2.3.2 Semiographic representations
2.4 Fourth parameter: Position
2.5 Fifth parameter: Density
2.5.2 Zero density
2.5.3 Partial density
2.5.4 Exhaustive density
2.6 Sixth parameter: Depth
2.6.2 Surface representation
2.6.3 Deep representation
2.6.4 Shallow (transparent) representation
Thomas G. Habing, Timothy W. Cole, and William H. Mischo. 2001. Qualified Dublin Core using RDF for Sci-Tech Journal Articles. https://dli.grainger.uiuc.edu/Publications/metadatacasestudy/HabingDC2001.pdf