In Modern Man in Search of a Soul, Carl Jung examines the spiritual crux of modern man: how to achieve spiritual happiness in a world that embraces consciousness while largely ignoring the unconscious mind:
To me, the crux of the spiritual problem of today is to be found in the fascination which psychic life exerts upon modern man. If we are pessimists, we shall call it a sign of decadence; if we are optimistically inclined, we shall see in it the promise of a far-reaching spiritual change in the Western world. At all events, it is a significant manifestation. It is the more noteworthy because it shows itself in broad sections of every people; and it is the more important because it is a matter of those imponderable psychic forces which transform human life in ways that are unforeseen and—as history shows—unforeseeable.
These are the forces, still invisible to many persons today, which are at the bottom of the present “psychological” interest. When the attractive power of psychic life is so strong that man is neither repelled nor dismayed by what he is sure to find, then it has nothing of sickliness or perversion about it.
Along the great highroads of the world everything seems desolate and outworn. Instinctively the modern man leaves the trodden ways to explore the by-paths and lanes, just as the man of the Græco-Roman world cast off his defunct Olympian gods and turned to the mystery-cults of Asia. The force within us that impels us to the search, turning outward, annexes Eastern Theosophy and magic; but it also turns inward and leads us to give our thoughtful attention to the unconscious psyche.