Most Hindus venerate one or more deities, but regard these as manifestations of Ultimate Reality. The Ultimate Reality that is behind the universe and all the gods is called by different names, but most commonly Brahman (not to be confused with the creator god Brahma or the priestly class of Brahmans). In the Rig Veda, Ultimate Reality is referred to as "the One." In the Purushasukta, it is "Purusha," and in the Upanishads it is called "Brahman," "the One," and several other names. Most modern Hindus refer to the Ultimate Reality as Brahman. The Upanishads describe Brahman as "the eternal, conscious, irreducible, infinite, omnipresent, spiritual source of the universe of finiteness and change." Brahman is the source of all things and is in all things; it is the Self (atman) of all living beings. Brahman is impersonal Being in itself, but it can be known through the many gods and goddesses that are manifestations of Brahman. In science when you can not explain a medium they invented ETHER. "A medium of great elasticity and extreme tenuity, supposed to pervade all space, the interior of solid bodies not excepted, and to be the medium of transmission of light and heat; hence often called luminiferous ether." The closest thing in science to Brahman is ether. Some of us confuse the word "GOD" to be "Brahman" and bash others, but happily accept Ether as it is scientific. The ultimate end of every Hindu's life is moksha, which can be understood in a variety of ways: liberation from rebirth, enlightenment, Self-realization, or union with Brahman. This is considered to the be the highest purpose of life, although very few can achieve it in a single lifetime and there are a variety of paths to attain it.