Vibratory Levels....

We on planet Earth exist on the dense physical level with a relatively low rate of vibration. Our vision or perception along the total vibration scale is restricted to a limited range extending from the low frequencies of sound (16 to 20,000 cycles per second), to the higher visible light frequency spectrum of the physical level ranging through red, orange, yellow, green, blue and violet to the point where our vision ceases at the ultra-violet light level. We are unable to see the higher-vibration worlds which surround and interpenetrate us unless we ourselves can raise our own vibration levels to their higher level. Similarly we can only see Beings from other planets or their space craft when they choose to lower their vibration levels down to our own dense physical level.
If we now view the evolutionary path in the context of vibratory levels, we begin the evolutionary journey on the high soulic spiritual plane, traveling down through the etheric (mental), and the astral (emotional) levels. The first half of the evolutionary cycle thus takes the soul down into denser and denser matter, in which the individualization of the soul is developed. As the soul passes down through progressively denser realms it manifests in correspondingly coarser bodily form, finally arriving upon the lowest frequency level, the physical realm, which we experience here on Planet Earth.
The Spirit World has as many distinct planes of existence as an onion has skins, each forming an outer protecting skin to the previous one and providing a means of contacting the experiences which that particular plane has to offer. These planes are co-existent with our physical world, invisible to our slow reacting sense of sight, yet as real as the invisible waves which carry our radio programmes.
As a Spirit descends, plane by plane, into the depths of experience, a body, complete with the organs of sense suitable for manifestation in that particular sphere, has to be donned in order that those senses may respond to the vibration of things comprising that sphere.
Without such a garment it would not be found possible either to express oneself or to receive impressions in local surroundings, and the experiences in that particular plane would be fruitless.