Inferred Nature
Barfield distinguishes between inferred nature and familiar nature. Inferred nature cannot be perceived without the aid of instruments (if it is ever perceived at all). Only this nature, modern science assumes, is truly independent of human senses and thinking (see WA 52-53).

Inferred nature is "the base we arrive at by thinking really hard about familiar nature with the help of experiments, that is by science" (WA 86).

Barfield sometimes refers to inferred nature as "the particles" or "the unrepresented."
 

See in particular Worlds Apart, passim.