The optimum population," said Mustapha Mond, "is modelled on the iceberg — eight-ninths below the water line, one-ninth above. - Aldous Huxley

At the core of the Perennial Philosophy we find four fundamental doctrines.
First: the phenomenal world of matter and of individualized consciousness — the world of things and animals and men and even gods — is the manifestation of a Divine Ground within which all partial realities have their being, and apart from which they would be non-existent.
Second: human beings are capable not merely of knowing about the Divine Ground by inference; they can also realize its existence by a direct intuition, superior to discursive reasoning. This immediate knowledge unites the knower with that which is known.
Third: man possesses a double nature, a phenomenal ego and an eternal Self, which is the inner man, the spirit, the spark of divinity within the soul. It is possible for a man, if he so desires, to identify himself with the spirit and therefore with the Divine Ground, which is of the same or like nature with the spirit.
Fourth: man's life on earth has only one end and purpose: to identify himself with his eternal Self and so to come to unitive knowledge of the Divine Ground.

Half of the human race lives in manifest obedience to the lunar rhythm; and there is evidence to show that the psychological and therefore the spiritual life, not only of women, but of men too, mysteriously ebbs and flows with the changes of the moon. There are unreasoned joys, inexplicable miseries, laughters and remorses without a cause. Their sudden and fantastic alternations constitute the ordinary weather of our minds. These moods, of which the more gravely numinous may be hypostasized as gods, the lighter, if we will, as hobgoblins and fairies, are the children of the blood and humours. But the blood and humours obey, among many other masters, the changing moon. Touching the soul directly through the eyes and, indirectly, along the dark channels of the blood, the moon is doubly a divinity.

For particulars, as everyone knows, make for virtue and happiness; generalities are intellectually necessary evils. Not philosophers but fretsawyers and stamp collectors compose the backbone of society.