Though path breaking in several respects, Special Relativity was limited in scope in that it did not incorporate the effects of gravity.
So Special Relativity in quantitative physical terms is based on relative comparisons of phenomena travelling at a constant velocity.
In corresponding qualitative psychological terms, Special Relativity is based on relative comparisons of phenomena that are interpreted within given stages of development (defined - as we have seen - by their dimensional numbers).
Einstein made an important breakthrough in his attempts to incorporate gravity in a more general theory when he realised in a moment of clear insight that - what we call - gravity is inseparable from the effect experienced through accelerated movement.
So for example when a car suddenly accelerates in speed one can feel a force pinning one to the seat that is identical to that of gravity.
This unlocked an important key for Einstein. He saw that he could include gravity in a General Theory by extending his findings regarding the relative nature of space and time in the Special Theory to now include accelerated - as well as constant - notions of velocity.
Once again a corresponding holistic qualitative extension exists that has important implications.
It took me some time to unlock this alternative explanation to my satisfaction. However close assocation with the work of the Spanish mystic, St. John of the Cross was eventually to prove rewarding.
St. John in his works deals with the higher stages of development specifically from a spiritual perspective.
For one following an authentic contemplative path, stages of illumination (when one is bathed in a new spiritual light) inevitably tend to be associated with corresponding stages of purgation (where one can become plunged in deep spiritual darkness).
What is surprising about St. John's approach however is that he places little emphasis on the value of the illuminative stages for authentic progress but rather on the dreaded "dark nights" that must be so painfully endured.
Indeed he is rather scathing of the faults of "proficients" who would already have reached a relatively advanced stage of development for - what he considers - an often mistaken attraction to the spiritual light breeding all kinds of spiritual imperfections.
Concentrating further on the precise reason for this problem can give a clear insight into the corresponding holistic counterpart of Einstein's equivalence principle!
Usually a new stage of illumination follows a previous stage of trial and darkness. During this difficult preceding period the spiritual light - while remaining hidden - incubates perhaps for a lengthy period in the unconscious. Then when the time is right - often in a dramatic new moment of conversion - it then becomes released in a conscious manner through new intuitive illumination. However as one dwells in this new light, it gradually interacts with phenomena. And inevitably as phenomenal life is restored (initially in a wonderful manner), secondary attachment sets in. This growing rigidity then leads to a gradual reduction in the dynamic interaction of polarities in experience. This can be accurately described as a decrease in the psychological velocity of understanding which is directly equivalent to a reduction in (psychological) gravity.
So the important point to register here is that just as - in holistic terms - (physical) light has a complement in (psycho-spiritual) light, likewise (physical) gravity has its corresponding counterpart in (psycho-spiritual) gravity.
As we know the force of (physical) gravity is much lower on the Moon than on Earth. So for someone on the Moon's surface, it is very difficult - literally - to keep one's feet on the ground.
Understood in appropriate fashion an exactly similar psychological explanation likewise exists (of which St. John of the Cross was keenly aware).
As phenomenal attachment increases (during the illuminative stages), psycho-spiritual gravity itself starts to decrease. When we think of it, this is even recognised in popular language usage. For example we might refer to a person as having "gravitas" which implies a degree of interior depth. However when the spiritual light shines, the focus of attention tends to become somewhat externalised. One then tends to develop more superficial interests thus lessening this sense of gravitas. This is even applicable to whole nations. For example Ireland spent a period of 15 years during the famed "Celtic Tiger" bathed as it were in a seemingly unending economic light. Unfortunately this subsequently led to a dramatic increase in the superficiality of people's concerns through growing materialism and selfishness that now - in deep recession - is proving very difficult to address.
The key problem that St. John points to - in the exalted context of spiritual "proficients" - is the danger of pride surfacing during the illuminative stages. Now pride is the direct opposite of humility which - literally - refers to a deep grounding in (true) reality. So when pride takes over, one loses the ability to keep one's feet (psychologically) on the ground thereby becoming prone to all kinds of illusions. Once again using the Celtic Tiger analogy, as a people we - quite literally - got "carried away" (due to a considerable reduction in psychological gravity) during the boom years with consumer behaviour reaching manic proportions.
So just as St. John would associate the illuminative stages with a decrease in psychological gravity (leading to the danger of pride) he would see the corresponding purgative stages as vital for restoring necessary balance. Here one can become properly grounded again in reality through a spirit of true humility. (Likewise in economic terms a severy recession may be necessary to cure the manic psychological behaviour of the preceding boom!)
Indeed this helps to explain why the onset of the purgative stages can be so disconcerting. Because of the increased speed of interaction with respect to opposite polarities in experience (representing a corresponding increase in spiritual gravity) former attachments are revealed as key impediments to progress. And as these attachments are painfully eroded, one experiences a deep sense of loss.
Now when one experiences loss it leads to the feelings of grief. And here in the word "grief" we have the direct psychological counterpart to the physical notion of gravity.
So becoming established in higher dimensional stages of development requires a preceding period of purgation (through which dynamic interaction i.e. velocity as between opposite polarities in experience greatly accelerates). Not surprisingly such purgative periods are intimately associated with deep feelings of grief (in the experience of psychological gravity).
Thus each higher stage of development is thereby more dynamic i.e. characterised by a greater speed of psychological interaction than its predecessor. In the limit where such speed approximates its maximum, phenomena no longer even appear to arise in experience with the pure light of Spirit now solely remaining. And such a state of pure union is the ultimate goal of the contemplative life!