According to J.L. Ackrill, a key to understand his fourfold classifications of things we must understand two different notions:
- "Being in something as a subject"
- "Being said of something as a subject"
The first one, according to him, set up the difference between "substantial" and "non-substantial" and the second one between "species and general" from "individuals".
So, from there, we might have:
- Species and genera in the category of substances.
- Species and genera in the category of non-substances.
- Individuals in the category of substances.
- Individuals in the category of non-substances.
I have some questions:
- What counts as a subject?
- How is being "in something" equivalent to "substance"?
- How is being "said of something" equivalent to "species and genera"?
- What is the relationship between "Substances" and "Species and genera"?
Extra: Some source with a more simple way to get into this idea?