The ladder of abstraction is one of the most useful models of thinking and writing. S.I. Hayakawa made the model popular in his 1939 book Language in Action. Since then, the ladder has helped people think clearly and express what they mean.
At the bottom of the ladder are concrete terms – things that are available to our senses and have specific meanings. Hayakawa used the example of Bessie the cow.
At the top of the ladder are abstract terms – things that do not refer to things in the physical world and have multiple meanings. At the highest level of abstraction, Bessie becomes wealth.
Good writing relies on concrete terms and mixing the concrete with more abstract terms. See for example this great essay from Roy Peter Clark:
Ted Hughes in his book Poetry in the Making stresses the importance of using words that appeal directly to the senses, as they trigger our imagination.
Science and art use the ladder of abstraction differently.
Douglas Hofstadter noted, “Science is about classes of events, not particular instances.” Science develops theories about classes of events and puts those theories to the test with experience.
Art is the opposite. It deals with specific things and events. It may well move from the concrete to the abstract – and have things to say about life, death, love, and meaning. But it always starts from the concrete.