Pancha-Kosha or 5 Sheaths

The Yogic view says that we are not just a physical dimension, and that we're composed of other subtler, perceptive, subconscious, transcended layers as well : the 5 layers or Koshas or sheaths, almost like onionskins. Nourishing one Kosha in turn nourishes the next consecutive Kosha and so on and so forth. Yoga focuses on re-establishing the harmony between the different Koshas for the highest state of wellbeing imaginable.

The first   is the Annamaya Kosha : Anna meaning Food, hence the Food layer. This is our Physical layer, that is comprised of skin, muscle and bone. Annamaya Kosha is nourished by Asana Practice and other holistic forms of excercise, and the intake of the right food.

The second is the Pranamaya Kosha : Prana  meaning the universal life force that drives us. This is also Physical, yet a layer deeper and comprises of the respiratory, circulatory, digestive, excretatory, nervous, glanduler and reproductive systems. Pranamaya Kosha is nourished by Pranayama Practice (the practice of working with Prana using breathing methods) and a healthy Annamaya Kosha.

The third is the Manomaya Kosha : Mano meaning the mind and perception that gives rise to thought and emotion. This is the first non-physical layer. Manomaya Kosha is nourished by Dhyana or Mediation. Mantra Chanting (or for that matter, immersing yourself in song, music, dance) also accesses and nourishes the Manomaya Kosha, by eliminating thought, and quietening the drunken monkey called the Mind. Manomaya Kosha is also nourished by a healthy Pranamaya Kosha.

The fourth is the Vigyanamaya Kosha : Vigyan meaning Wisdom or Understanding. Vigyanamaya Kosha is nourished by Dhyana / Mediation, Dharana / Contemplation and reflection. This is a state that naturally arises when the previous three layers are nourished. It is made up of transcended thoughts, free of self-centrednes and is concerned witht the welfare of all.

The fifth is the Anandamaya Kosha : Ananda meaning Bliss or Uncondtional Happiness. It is a state of being. It is joy without any reason, and does not need anything to generate happiness. Anandamaya Kosha is reached by nourishing all the previous layers and can be reached both systematically or sponataneously. We have all accessed this layer at many instances in our lives, for example when something of great beauty or wonder brings us joy such as an amazing sunset.

This was first penned down in the Taittiriya Upanishad . There are hundreds and thousands of writings and interpretations of this today. A quick glance in more detail can be found here.

It's quite obvious and very scientific, I think.