Why are odd and even considered a philosophical illusion?

Why is the concept of odd and even a
philosophical illusion?

Because when you look numbers (odd & even are numbers) numbers aren't based on reality, but themselves concepts & representations of things.

So, odd & even are a step further in representing a representation of a thing...hope that makes sense.

Consider the number 1 - it's a place holder, for a single quantity of *something*...similar with 2, which is a placeholder for two quantities of the same thing. However, the problem is that you can't have two items that are exactly the same, according to the laws of physics, because they're made up of different sets of atoms. Thus the two objects which make up the 'pair' of objects, while close, are not exactly the same.

It's been a long, long time since I took a couple of philosophy courses in university, perhaps somebody else has a better way of explaining this - in any event, hope this was helpful. Good luck.

because they are