This single, unitary divinity had several aspects and names in the Upanishads, one of the most important of which is Atman, a word that originally meant "breath" or "soul" or "vital principle" (as the word "Atmen" does in German). As a cosmological principle or deity, Atman seems to be something like "universal soul" or "universal spirit." In the Brihad-Aranyaka Upanishad , Atman is explicitly called a Person that created the universe by first splitting himself into male and female halves. In the Chandogya Upanishad, this single god is called Brahman, and is "the One without a second"; this Brahman is not only the principle and creator of all there is, but is also fully present within each individual.