Of course they can. Carbon dioxide consists of quarks and electrons. I can divide it into units smaller than atoms and it's still quarks and electrons. All you did was a word trick by assuming a specific meaning of “substance”.

No word trick. Just pointing out that there's some nuance to it.

> Carbon dioxide consists of quarks and electrons.

But this is just plain wrong. Carbon dioxide consists of carbon dioxide molecules. There is no "carbon-dioxidity" to the quarks and electrons (which are also made of quarks) that the atoms that make the molecules can be broken down into.

That's a good point, I hadn't thought about it that way. Maybe it's a little less of an arbitrary choice than I was giving it credit for.

It is not, however, Democratus's point. So I think the "words change, deal with it" argument still stands.