Let's talk about cats to discuss this idea of suchness and muchness. Suchness will be referred to catness, and muchness to cattiness. No cats will be harmed in any following thought experiments.
The suchness of cats is what makes something a cat, that's to say, it's about being a cat as such and whether said something be a cat or not. Through some happenings or changes, if a thing gains the suchness of cats--or catness, then it becomes a cat, but if a thing loses its catness, then it ceases to be a cat.
Example: This thing has catness, therefore, it is a cat. This other thing has no catness, therefore, it is not a cat.
The muchness of cats is about how catty something is, that's to say, something can be more or less catty regardless of whether we can count this cattiness or not. The muchness of cats--or cattiness--implies having a degree of catness in the first place, but having catness does not imply there being a size or degree of any sorts, thereby, changing the cattiness of a thing does not change whether said thing be a cat or not, only more or less.
Example: This thing is cattier than this other thing, or that thing is less catty than this thing. If we can count it, we can for example say that the first thing has 50 cattiness and the other thing has 25 cattiness, therefore, the first thing is twice as catty as the other thing.
