The Zen philosophy seems in several ways to be a very practical system in stimulating an awakening of the "Spiritual Qualities" by inducing spontaneity in mental reactions. It suggests that the methods used make an instantaneous connexion through the human apparatus to the Buddhic layer of consciousness. The resulting illumination and oneness, called Satori, would appear to be a matter of degree, and not necessarily of very great range, but belonging to the sub-plane and fields of knowledge and experience which are related to that degree.
The essential feature is that this inner light breaks through the ratiocinative processes of the Mind, and enables the entitative self-consciousness to receive something of the state of "things in themselves," and yet be able to translate the experience in terms of feeling and knowledge and action on the human plane. Its value to us appears to be in the growing ability to spontaneously react rightly in any circumstances and on all occasions; but I imagine that this right reaction would be an individual matter and by no means apply to anyone else — karmic considerations would be the main governing factor.
The flash of illumination would bring a deeper understanding by which volitional action could be exhibited more accurately and wisely; for, after all, as humans, we have to develop Manas, even though we need the greater "awareness" which Buddhi gives.
The Theosophical ForumTHEOSOPHICAL UNIVERSITY PRESS ONLINE