I went back and painfully searched the text until I found the word. Don't ask me what it means. But for a guess it is something about the importance which we attribute to matter.

Then in
Metaphysics: what difficulties concerning entity in abstract, substantial
forms, hylarchic principles, plastic natures, substance and accident,
principle of individuation, possibility of Matter’s thinking, origin of ideas,
the manner how two independent substances so widely different as Spirit
and Matter, should mutually operate on each other? what difficulties, I s