Reading Aristotle's logic. He treats "attributes" as real entities, just as mathematicians sometimes treat numbers as real things, much to my disdain. Thus, he talks about "essential attributes" -- those which cannot be separated from the thing while the thing remains what it is (e.g. "wet" is an essential attribute of "water" -- if it's not water, it's not water) and "accidental attributes" -- those which can be separated from the thing and yet the thing remain what it is (e.g. "black" is an accidental attribute of "dog" because a dog may be black, but may also be something other than black and still be a dog).
This strikes me as reflecting the same Realism as sometimes shows up in math -- treating "2" is a real entity, rather than merely a linguistic tool we use to describe a particular group of items in reality, or a particular concept in pure math. Or how we sometimes describe "perfection" as a real entity or attribute, rather than simply a linguistic tool we use to describe something that embodies what we wish it to be for a particular purpose.
But these attributes, like numbers, are merely artifacts of our categorization. "Brown" may be an accidental attribute of "dog," but not of "chocolate lab." The attributes have no real existence, except insofar as they are useful ways of categorizing reality in a way we can comprehend.
Does that make the labels useless? By no means. But once we start treating those labels as real, it seems to me that we get in trouble. In this case, we start arguing about whether a particular attribute is "essential" or "accidental" with respect to a particular entity. Is God "necessarily perfect" as Anselm argued? The whole discussion, unfortunately, is meaningless -- an argument over labels, and without substance.
That fundamental distinction between "reality" and "concept" makes thought so much clearer.
Concept is our way to describing reality, because without concept, we cannot relate to reality. Concepts without corresponding physical reality may be useful (e.g. "Love" describes a particular state of mind, but has no defined physical reality) -- however, they should not be treated as having reality as an entity (e.g. "God is Perfection and Perfection existsn, therefore God exists").