Zen masters wish us to see into that unconscious consciousness which accompanies our ordinary dualistically-determined consciousness. This is a sort of undifferentiated knowledge, knowledge of non-distinction, sometimes called transcendental Prajna-knowledge.
In Buddhism, generally two forms of knowledge are distinguished: one is Prajna and the other is Vijnana. Prajna is all-knowledge, or transcendental knowledge, i.e. knowledge undifferentiated. Vijnana is our relative knowledge in which subject and object are distinguishable, including both knowledge of concrete particular things and that of the abstract and universal.
Prajna underlies all Vijnana, but Vijnana is not conscious of Prajna and always thinks it is sufficient in itself and with itself, having no need for Prajna. But it is not from Vijnana, relative knowledge, that we get spiritual satisfaction. However much of Vijnana we may accumulate, we can never find our abode of rest in it; for we somehow feel something missing in the inmost part of our being which science and philosophy can never appease.
Science and philosophy do not apparently exhaust Reality; what is still left in Reality, according to Buddhism, turns towards Prajna for its recognition. Our spiritual yearnings are never completely satisfied unless this Prajna is awakened, whereby the whole field of consciousness is exposed, inside and outside, to our full view. Reality has now nothing to hide from us.
---from "Living by Zen" by D. T. Suzuki