There are, to begin with, constant facts of experience which make the realization of the divine presence not only a satisfaction, but the indispensable "staff of life" for certain human beings. In their unfaltering faith in God's enduring and proximate actuality lies their sole source of security and trust. For such persons a lapse or a lack of faith is the prelude to utter collapse. A vague general assurance of the dependability of the future is, for most people, a prerequisite for a sane and untroubled existence. Even those who live in unreflective satisfaction with the fruits of the moment would find these moments less satisfactory were they not set in a background of reasonably fair promise. The exuberant optimist, when he stops to reflect, has a buoyant and inclusive faith in the essential goodness of man and the universe. Whitman stands out in this connection as the classic type. Evil and good were to him indifferently beautiful. He maintained an incredibly large-hearted and magnanimous receptivity to all things great or small, charming or ugly, that lightened or blackened the face of the planet. While the average man accepts the universe with a less wholesale and indiscriminate appreciation, yet he does feel vaguely assured that the nature of things is ordered, harmonious, dependable, and regular, that affairs are, cosmically speaking, in a sound state. He feels a vast and comfortable solidity about the frame of things in which his life is set; he can depend on the familiar risings and settings of the sun, the recurrent and assured movement of the seasons. Were this trust suddenly removed, were the cosmic guarantee withdrawn, to live would be one long mortal terror. That this is precisely what does happen under such circumstances, the voluminous literature of melancholia sufficiently proves. The sense of insecurity takes various forms. Sometimes the patient experiences a profound and intimate conviction of the unreality of the world about him. His whole physical environment comes to seem a mere phantasy and a delusion. In some cases he finds himself unmoved by the normal interests and excitements of men, unable to find any stimulus, value, or significance in the world. Esquirol observed the case of a very intelligent magistrate.... Every emotion appeared dead within him. He manifested neither perversion nor violence, but a complete absence of emotional reaction. If he went to the theater, which he did out of habit, he could find no pleasure there. The thought of his house, of his home, of his wife, and of his absent children, moved him as little, he said, as a theorem of Euclid.[1] [Footnote 1: Ribot: _Psychology of the Emotions_, p. 54.]