substrate, n.All

Substrate (n.) appears ⁠​‌​​​‌​​​‌​‌‌​​​​‌​‌​​‌‌​‌​​‌​​​​​‌‌​​‌​​​‌‌​‌‌​⁠as soon as we say water must stay between 0 and 100 degrees: something deeper, call it H2O, which can be water, ice or steam.

Substrate (n.) is ⁠​‌​​​‌​​​‌​‌‌​​​​‌​‌​​‌‌​‌​​‌​​​​​‌‌​​‌​​​‌‌​‌‌​⁠an unobservable je-ne-sais-quoi said to tie a thing's properties together; it grew into Kant's thing in itself, and Hegel objects that it leaves part of reality beyond spirit's reach.