The Dark Night is the psychological equivalent of the physical Black Hole. Just as it is now accepted that there are - in physics - "White Holes" as well as Black Holes, equally in the spiritual life there are "Bright Nights" as well as Dark Nights.
Black Holes through radiation of virtual particles can becomes less black (i.e. "White Holes") and indeed ultimately become transformed into pure physical energy.
Likewise Dark Nights can also radiate through the refined emission of projected fantasies. They thereby can become less dark (i.e. "Bright Nights") and ultimately be transformed into pure spiritual energy (i.e. mystical union).
The Dark Nights - as stressed by St. John of the Cross - involve the transcendence of all psychic matter in experience. Conventional knowledge of space and time undergoes a profound reversal gradually being swallowed up in the fierce gravitational pull of the inner journey. (Indeed St. John alludes to this in referring to the story of Jonah and the whale).
However, as well as the transcendent journey of the Dark Night (The Ascent of Mount Carmel), there is the corresponding immanent journey of "Bright Nights" where now psychic matter is projected outwards from the unconscious.
Thus we have two Universes or Worlds:
1) the transcendence of psychic matter, where the World of (conscious) experience is sucked into the unconscious.
2) the immanence of psychic matter, where - in reverse form - the World of unconscious experience is projected out in phenomenal form.
Thus the (conscious) World without is pulled in one direction inwards. The (unconscious) World within, is expelled in the opposite direction outwards.
Using Eastern categories, the Dark Nights would correspond to important stages of the Subtle Realm. The more comprehensive synthesis of Dark Nights of the Soul and "Bright Nights" of the Soul would correspond to the causal realm.
St. John does deal with the Dark Night stages in great depth. He also deals to some extent with the "Bright Night" stages in his "Spiritual Canticle", but mainly in terms of poetic imagery, and does not satisfactorily integrate them within his formal intellectual framework.
In psychological terms, we also have a corresponding phenomenon to the singularities of the physical world. Just as a physical singularity goes beyond any finite notion of matter, likewise a psychological singularity goes beyond any finite notion of understanding. This point, this centre of being is often referred to as the "void".
Just as there are two singularities recognised in black hole physics, there are two such singularities in psycho-spiritual development
1) The void at the culmination of the Dark Night that represents the climax of the Subtle Realm. This involves a considerable level of detachment from direct or voluntary conscious activity in what is a transcendent void.
2) The void at the culmination of the dark-bright (i.e. dim) night that represents the climax of the Causal Realm). This involves a high level of detachment from both direct voluntary and indirect involuntary conscious activity. This can be referred to as the immanent-transcendent void which signifies the completion of the inner journey.
Amazingly, there is also a corresponding phenomenon in psychic terms to event horizons.
One approaches the (psychological) event horizon in finite space and time through mortification and purification of voluntary desires (in what St. John refers to as the active nights).
However one cannot achieve - by effort alone - entry into the inner regions of the unconscious. Access to this highly confusing world of non-linearity requires a special non-conscious boost in a subtle mode of intuitive understanding (in what St. John refers to as the passive nights).
Thus one approaches the event horizons through refined conscious effort in the active nights. One actually crosses through the event horizons in the passive nights (where space-time becomes highly curved and dominated by intuitive rather than rational understanding).
Actually, the similarities go further in the psychological counterpart of non-spinning and spinning Black Holes.
Physicists distinguish as between outer event horizons (non--spinning black holes) and outer and inner event horizons (spinning black holes)
In psychological terms, the outer event horizon corresponds to what St. John refers to as the Dark Night of the senses'. (One approaches this event horizon in the active night; one passes through in the passive night).
To enter the centre of spiritual nakedness - the void or singularity - one has to pass through both outer and inner event horizons.
Now, St. John himself discusses the fact that while comparatively many in the spiritual life pass through the outer event horizon (i.e. travel through the nights of sense), very few continue the journey through the inner event horizon (and experience the nights of spirit).
A fascinating key to this, lies in the nature of personality. The first personality group are too stable and conventional to ever radically depart from conventional experience and correspond to non-spinning black holes.
The second group are often intense, creative and highly strung in personality with a marked capacity for the unusual or "abnormal" experience. They are frequently gifted with an innate capacity for the transcendental and correspond to spinning black holes.
However, though St. John describes very well the journey inwards to the centre of the unconscious, he does not really deal adequately with the equally important return journey. Using his mountain analogy he describes superbly the ascent (transcendence). However he does not deal adequately with the equally important descent (immamnece).
In journeying outwards from this deep inner centre, one encounters again the inner event horizon (now moving in the opposite direction!). This corresponds to that spiritually refined erotic experience (i.e. "Spiritual Espousal") which represents a "Bright Night of the Spirit".
Then there is the final (reverse) encounter with the outer event horizon involving very intimate exposure to physical erotic fantasy. (St. John only hints at this stage). This represents a 'Bright Night of the Senses' in this "imaginary" return journey.
Thus to attain mystical union one must complete two journeys:
1) the inward (transcendent) journey to the unconscious eliminating attachment to all "real" (i.e. conscious) experience.
2) the outward (immanent) journey from the unconscious this time erasing all projected "imaginary" fantasy (i.e. unconscious) experience.
Whereas the inner journey is characterized by Dark Nights (of Sense and Spirit), the outer journey is characterised by Bright Nights (of Spirit and Sense). It is the brightness of these nights that periodically lights up the darkness and leads to the gradual dawning of the light (and mystical union). This is typically referred to in the literature as dim (rather than dark) contemplation.
The Subtle Realm (jnanas of form), relate to the first journey (in the psychological equivalent of the physical Black Holes).
The Causa1 rea1m (formless jnanas), relate to the second journey (in the psychological equivalent of the physical "White Holes").