Intellectual Soul
The idea of the intellectual soul is borrowed from Anthroposophy. Although Barfield admits that "there is really, by the very nature of the subject, an almost insuperable difficulty about describing or 'explaining' the intellectual soul, as seen from within, that is to say, from the Ego itself" (RCA 126), he succeeds admirably in helping us to understand its stance before the world.

"We in the West," he explains in Romanticism Comes of Age, "are so placed [in the Intellectual Soul] that

    as our self-consciousness increases, we feel: over there is the material world, all that I experience as sense-perception and ordinary thought, and over here is the "I," a mysterious entity, perhaps non-entity) about which I can never know anything, and between the two there is no connection. (132)
While the Consciousness Soul "only says 'I know,' when it can add: 'because I have experienced,'" the intellectual soul knows things, or thinks it does, with certainty without the need of "suffering" them. Its knowledge is abstract.
 
See in particular "Of the Intellectual Soul" (RCA 126-142).