Hi John D I hope you don’t mind me chiming in. I find it odd that WLC rejects Platonism since theism to my understanding is rooted in Platonism. But no, abstractions do not exist “out there” they only exist in the mind. Such as numbers, the government, transportation, and the boggieman, etc. Some of these abstractions are valid and some are not. For example one can argue that numbers are a valid abstraction (or concept) because they refer directly to particulars in reality. The same cannot be said of the boogieman and in my opinion gods or governments. I think you might find Ayn Rands book “Introduction to Objectivist Epistemology” of great insight on the topic of abstract concepts. Though I’m not an Objectivist this book really changed how I think about things.