ELI5: Explain Like I'm 5

Conceptualist realism

Conceptualist realism is a way of thinking about the world. It suggests that everything is made up of ideas, or concepts, which we can understand and talk about, but these concepts are also part of a bigger "real" world. This means that even though things like numbers, shapes, and colours are just concepts that we have created, they still exist and interact with the universe around us. So, even though we may not be able to see or touch a number or shape, they are still real and we can talk and think about them in the same way as we talk and think about the things that we can see and touch.