Each science has a subject matter and a method. Medicine → human body as it is healthy or diseased.
Sciences study beings, not being qua being (Heidegger again).

How do we arrive to a system of categories?
Start with predication. “Socrates is wise” - Socrates (subject) is wise (predicate).

Given that we can use “wise” in different contexts, but not “Socrates,” we can say that these predicates are an ontological ground for a category system.

Inherence: being-in the subject or not being-in the subject.

A dependent being is “in the subjects,” as it doesn’t exist outside it.

said-ofnot said-of
not being-inuniversal substanceparticular substance
being-inuniversal accidentparticular accident