John,
Let's write down my dissenting opinion:
Diagrams are geometrical structures (special kind of pictures, figures, usually labeled) chosen by humans to help with representations, explanations and reasoning.
Let's just note this difference.
Alex
Alex,Both dictionaries I quoted (and others I did not bother to quote) make a very clear distinction between structures (as patterns that exist independently of what anybody may think or say about them) and diagrams (as patterns that people or animals or computers choose to represent for explaining or reasoning about structures).And thank you for the definition from Wikipedia, which makes exactly the same distinction and emphasizes that it goes back to prehistoric times (over 10 thousand years ago). Euclid and other geometers (more than 2,000 years ago) adopted diagrams for the foundation of mathematics, especially geometry -- and those diagrams are also used for reasoning and for applications in science, engineering, and architecture.And thank you for the three citations to the Stanford articles. The one on diagrams discusses the writings by C. S. Peirce, and it also cites two things by me: (1) My book on Knowledge Representation, published in 2000, and (2) an article I wrote in 2011, which was published in the journal Semiotica: https://jfsowa.com/pubs/egtut.pdf The article about the structure of scientific theories admits that humans may have discovered and stated the theories. But it focuses on the patterns in the theory that are independent of the scientists who discovered or stated them. Their primary example is Newtonian mechanics, but it ignores anything that Newton himself thought or did. I discusses only the mathematical patterns.Today, we know that the mathematical pattern of Newtonian mechanics is only approximately true about the universe. But the patterns implied by that theory exist (in a mathematical sense) independently of what we think about them. When considered as a mathematical formula and the collection of patterns implied by that formula, it is independent of what anyone may think about those patterns..The article about structural realism admits that some people might consider structures as things that people built or imagined. But it also makes a case that the structures that are really real -- they exist independently of what anybody may think about them.In summary, the American heritage definition of diagram is as good as any and better than most:
- A plan, sketch, drawing, or outline designed to demonstrate or explain how something works or to clarify the relationship between the parts of a whole.
- A graphic representation of an algebraic or geometric relationship.
- A chart or graph.
This implies that diagrams are chosen by humans for explanations and reasoning. Structures are patterns considered as existing by themselves. The processes that create the structures (human or non-human) are not relevant to their existence as structures. Unless anybody can find any better terminology for any application of ontology, I believe that this distinction is the best we have.JohnFrom: "alex.shkotin" <alex.shkotin@gmail.com>IN ADDITION"A diagram is a symbolic representation of information using visualization techniques. Diagrams have been used since prehistoric times on walls of caves, but became more prevalent during the Enlightenment.[1] Sometimes, the technique uses a three-dimensional visualization which is then projected onto a two-dimensional surface. The word graph is sometimes used as a synonym for diagram."