You're making too much of it. Tell me what a concept is. Do it without describing or naming the attributes of a concept.
Tell me what any particular concept is. Do it without describing or naming its attributes.
Of course you can't, because that is what anything is.
For example:
What is the concept "dog?" If I say, the concept "dog" is the concept that identifies four legged animals of the canine genus, (assuming it is correct) what I have just written are the attributes of the concept dog, namely, "an identification," restricted to "four legged animals," and "canines."
Hank
Well, this is a philosophy thread. We're supposed to use lots of big words to beat stuff to death.
Anyway, I said the concept [of dog] is in our minds, because if we all vanished, there wouldn't be any concepts. There would still be dogs, with all of their attributes, but no concept of "doginess."