I feel pretty much the same way about Prime numbers. They're nothing but holes left when you mark all the composite numbers. Being prime isn't a property, it's

I feel pretty much the same way about Prime numbers. They're nothing but holes left when you mark all the composite numbers. Being prime isn't a property, it's the absence of the property of being composite--like calling black a color. But because prime numbers are so interesting and useful we call this background shape as if it's the foreground and even speak of non-prime numbers. Gödel, Escher, Bach has plenty to say about foreground vs background, inside vs outside.