Nay, we can see against the sun "the eagle soaring above the tomb of Plato," and in Paul, as in Plotinus, we can catch that sense of self-fulfilment in self-absorption, of rapture, of deliverance, which the highest minds have bequeathed to us as the heritage of their highest hours. These our spiritual ancestors are no eccentrics nor degenerates; they have made for us the sanest and most fruitful experiment yet made by man; they have endeavoured to exalt the human race in a way in which it can in truth be exalted; they have drawn on forces which exist, and on a Soul which answers; they have dwelt on those things "by dwelling on which it is," as Plato has it, "that even God is divine." CHAPTER IV SLEEP δλβἱα δ' ἑπαντες αἱσα λυσἱπονον μετανἱσσονται τελευτἁν. καἱ σὡμα μἑν πἁντων ἑπεται θανἁτὡ περισθενεἱ, ξὡὁν δ' ἑτι λεἱπεται αἱὡνος εἱδωλον' τὁ γἁρ ἑστι μὁνον ἑκ θεὡν' εὑδει δἑ πρασσὁντων μελἑων, ἁτἁρ εὑδὁντεσσιν ἑν πολλοἱς ὁνεἱροις δεἱκνυσι τερπνὡν ἑφἑρποισαν χαλεπὡν τε κρἱσιν. --PINDAR. The preceding chapters have carried us two steps upon our way. In Chapter II. we gained some insight into the structure of human personality by analysing some of the accidents to which it is subject; in the third chapter we viewed this personality in its normal waking state, and considered how that norm should be defined, and in what manner certain fortunate persons had integrated the personality still further by utilising uprushes of subliminal faculty to supplement or to crystallise the products of supraliminal thought. The review of these two chapters indicates clearly enough what my next step must be. It is obvious that in my review of phases or alternations of personality I have left out of sight the most constant, the most important alternation of all. I have thus far said nothing of _sleep_. Yet _that_ change of personality, at least, has been borne in on every one's notice;--not, certainly, as a morbid curiosity, but as an essential part of life.