The first part of your excerpt is talking about "derived units." The last sentence says:
A derived unit for the mass is the gram. One kilogram is equivalent to 1000 grams.
Generally speaking, a "gram" (or kilogram) is a unit of weight. But I think that everyone agrees that mass is not weight.
I guess you could say something like "matter measures mass, which is a measure of inertia." So matter becomes a "measure of a measure."
But this is exactly the type of conceptual confusion I've been talking about.
They also say that mass is a property of matter, but it's unclear to me what that is supposed to mean, exactly. That makes it sound like a "subpart" of matter, not matter itself. That's one reason I quoted Locke, who said that matter has many properties, not just one.
Edited by Moronium, 15 April 2019 - 12:36 PM.