Psychologists sometimes divide men into the two extreme classes of extroverts and introverts. The extrovert is the typical active; always leaning out of the window and setting up contacts with the outside world. His thinking is mainly realistic. That is to say, it deals with the data of sense. The introvert is the typical contemplative, predominantly interested in the inner world. His thinking is mainly autistic, dealing with the results of intuition and feeling, working these up into new structures and extorting from them new experiences. He is at home in the foreconscious, has its peculiar powers under control; and instinctively obedient to the mystic command to sink into the ground of the soul, he leans towards those deep wells of his own being which plunge into the unconscious foundations of life. By this avoidance of total concentration on the sense world--though material obtained from it must as a matter of fact enter into all, even his most "spiritual" creations--he seems able to attend to the messages which intuition picks up from other levels of being. It is significant that nearly all spiritual writers use this very term of introversion, which psychology has now adopted as the most accurate that it can find, in a favourable, indeed laudatory, sense. By it they intend to describe the healthy expansion of the inner life, the development of the soul's power of attention to the spiritual, which is characteristic of those real men and women of prayer whom Ruysbroeck describes as:-- "Gazing inward with an eye uplifted and open to the Eternal Truth Inwardly abiding in simplicity and stillness and in utter peace."[89] It is certain that no one who wholly lacks this power of retreat from the surface, and has failed thus to mobilize his foreconscious energies, can live a spiritual life. This is why silence and meditation play so large a part in all sane religious discipline. But the ideal state, a state answering to that rhythm of work and prayer which should be the norm of a mature spirituality, is one in which we have achieved that mental flexibility and control which puts us in full possession of our autistic _and_ our realistic powers; balancing and unifying the inner and the outer world. This being so, it is worth while to consider in more detail the character of foreconscious thought.