In this development the vibrations of outer matter play the part of the steel, which, on striking flint, causes the life latent within the latter to dart forth. Each vibration which strikes the soul arouses therein a dormant faculty, and when all the vibrations of the universe have touched it, this soul will have developed as many faculties as that universe admits of, until, in the course of successive worlds, it becomes increasingly divine in the one Divine Being. In order that all the vibrations of which a universe is capable may reach the soul the latter must surround itself with all the different types of atoms that exist in the world, for every vibration is an atomic movement, and the nature of the vibration depends on the quality of the atoms in motion. Now, the first part of evolution consists in condensing round vital centres[60] (_souls_) atoms aggregated in combinations of a progressively increasing density, on to those that make up the physical plane; when the soul has thus clothed itself with the elements of all the planes, the resulting form is called a "microcosm"--a small Cosmos--for it contains, in reality, all the elements contained in the Universe. During this progressive development, the soul, which thus effects its "fall" into matter, receives from all the planes through which it passes and from all the forms in which it incarnates, varied vibrations which awake within it correspondingly responsive powers and develop a non-centred, diffused, non-individualised consciousness. In the second phase of evolution, the forms are limited, the vibrations they receive are transmitted by specialised sensorial groups, and the soul, hitherto endowed with a diffused consciousness, begins to feel varieties of vibrations that grow ever more numerous, to be distinguished from the surrounding world, to separate itself, so to speak, from everything around; in a word, to develop self-consciousness. This separation first takes place on the physical plane; it is made easier by hard, violent contacts, and the forms, in their turn, become more complex, varied, and specialised in proportion as the soul is the more perfectly individualised. When it has developed all the self-conscious responsive powers in the physical body, it begins to develop those faculties which have as their organs of transmission the finer bodies, and as planes of vibration the invisible worlds.