William Lane Craig denies the number zero.

[robvalue]

I don't think you need any maths training to be able to understand the difference between zero [of something] in reality, and the concept of "zero" as part of a closed abstract system, such as mathematics. It wouldn't even matter if "zero" never corresponded to anything in reality. It doesn't have to. Closed mathematical systems only have to be internally consistent. Some have no known relevance to reality.

Anyone who continues to conflate the abstract with the real is either ignorant or has an agenda of trying to slide in other things which exist only as concepts (according to evidence as-yet presented) into reality. (Arguments are not evidence of existence.) You can of course say that abstract concepts exist in their own way, that is fine. But they are still very different. Some correspond to existent things, and some do not. "Zero" does not correspond to an existent thing on its own. No numbers do. They have to be combined with something.