I don't understand. The "idea" of a table is an object that provides a level surface to place stuff on.
What am I missing? What is the interesting part?
You surely wouldn't call a boulder sticking out of the earth "a table", even if it did have a conveniently level surface to place stuff on? The point is that what we call "a table" is not just about function - it's also about form.
In my view, this is the basis of any philosophy – the confidence that some conception is (and must be) defined like you do it out of habit. Philosophy is psychology under cover. Ask a psycho what is a table and they will easily point at a heap of flesh and bones, or at their t-shirt. Table is a word. All philosophy does is an iterative pseudoagreement between human minds, which were randomly trained at verbalizing inputs. Sometimes it finds similar sounds, but that’s it.