What is the problem of universals and how does it impact our understanding of reality?

The problem of universals is a philosophical issue concerning the nature of abstract concepts like "redness" or "beauty" and how they relate to individual objects. It impacts our understanding of reality by raising questions about whether these abstract concepts exist independently or only in our minds, and how they are related to the physical world. This problem challenges our perception of reality and the way we categorize and understand the world around us.