Metaphysically speaking, all that is conditioned is illusory. The more material and solid the appearance, the further it is from reality and therefore more illusory. In more general terms, the truth is that the higher one rises through the planes of being, the closer one is to reality. Paradoxically, spiritual beings are relatively real and enduring while material things are illusory and transitory. In truth, it is the thought that the world is the closest to reality, and things become more illusory as they take on more of a phenomenal character.
However, the true importance of earth-life lies in the fact that it is the place where experience is to be gathered. It conditions, regulates and limits the growth of the soul. The experienced soul on the mental plane will make for itself a splendid instrument for its next earth-life while the inexperienced one will not though in each case, the only material available is that brought from the physical plane.
Thus, noble aspiration is a seed which the soul would work out into splendid realisation on the mental plane and bring back with it to the physical plane for its next incarnation. It carries the mental image which is to be materialised on the physical plane when opportunity and suitable environment presents itself. For the mind the mental plane is the sphere of creation and the physical plane is only the place for materialising the pre-existing thought.
The soul is an architect that works out its plans in silence and deep meditation and then brings them forth into the outer world where its edifice is to be built, out of knowledge gained in past life. The objective manifestation follows the mental meditation, first idea then form.
SUBPLANES OF THE MENTAL PLANE
(Symbolic representation of the 7 sub-planes of the mental plane.)
Characteristically the mental plane has been described as being divided into seven sub-planes, the seventh being the lowest and the first being the highest. Consequently the 7th, 6th, 5th and 4th i.e., the first four sub-planes belong to the lower mental or rupa i.e., form levels. The 3rd, 2nd and 1st i.e., the three higher sub-planes belong to the causal or arupa i.e., formless levels. Although each of the four lower heavens has their own peculiar characteristics, it must not be assumed that the soul divides its life on the mental plane between the various levels. On the contrary, the soul awakens to consciousness on the mental plane at that level which best corresponds to its degree of development. It is on that level it spends the whole of its life in the mental body. The reason for this is that the higher level may always include the qualities of the lower, as well as those peculiar to itself; its inhabitants almost invariably have these qualities in fuller measure than the souls on a lower level.
The article has been taken from the book Life Beyond Death by Anil Sharma