William Lane Craig denies the number zero.

[Edwardo Piet]

Hmmm.

"zero" the number exists as a concept. Zeroness as a thing beyond that doesn't exist.

"Blue" exists as a concept. Blueness exists beyond that as qualia and subjective phenomenological experience that is different and unique to everyone.

So blue and blueness exists in at least two senses but "zero" only exists in one sense.

Think about it in terms of voltages on a wire, positive to negative, and back; what is "zero voltage"?  It is the ground, the voltage that the Earth is at.

Well, I wasn't being metaphrorical.

Colors exist in the sense of qualia. Zero only exists as a concept.