Hinduism embraces a great diversity of beliefs, a fact that can be initially confusing to westerners accustomed to creeds, confessions, and carefully-worded belief statements. One can believe a wide variety of things about God, the universe and the path to liberation and still be considered a Hindu.
This attitude towards religious belief has made Hinduism one of the more open-minded religions when it comes to evaluating other faiths. Probably the most well-known Hindu saying about religion is: "Truth is one; sages call it by different names."
However, there are some beliefs common to nearly all forms of Hinduism that can be identified, and these basic beliefs are generally regarded as boundaries outside of which lies either heresy or non-Hindu religion. These fundamental Hindu beliefs include: the authority of the Vedas (the oldest Indian sacred texts) and the Brahmans (priests); the existence of an enduring soul that transmigrates from one body to another at death (reincarnation); and the law of karma that determines one's destiny both in this life and the next.
Note that a specific belief about God or gods is not considered one of the essentials, which is a major difference between Hinduism and strictly monotheistic religions like Christianity, Judaism, Islam and Sikhism. Most Hindus are devoted followers of one of the principal gods Shiva, Vishnu or Shakti, and often others besides, yet all these are regarded as manifestations of a single Reality.
The ultimate goal of all Hindus is release (moksha) from the cycle of rebirth (samsara). For those of a devotional bent, this means being in God's presence, while those of a philosophical persuasion look forward to uniting with God as a drop of rain merges with the sea.
The authority of the ancient scriptures known as the Vedas as well as that of the priests known as the Brahmans are two concepts that are fundamental to Hinduism and differentiate the faith from Buddhism and Jainism.
Most Hindus venerate one or more deities, but regard these as manifestations of Ultimate Reality. So who, or what, is the Ultimate Reality that is behind the universe and all the gods? In the Rig Veda, it is referred to as "the One." In the Purushasukta, it is given the name "Purusha," and in the Upanishads it is called "Brahman," "the One," and several other names.
The Sanskirt word karma means "actions" and refers to the fundamental Hindu principle that one's moral actions have unavoidable and automatic effects on one's fortunes in this life and condition of rebirth in the next.
Hinduism is a decidedly theistic religion, but it can be difficult to determine whether it is a polytheistic, pantheistic, or even monotheistic religion. Of course, this is chiefly a western question: the Indian mind is much more inclined to regard divergent views as complementary rather than competing.
In Hinduism, there is not just one purpose of human life, but four: Dharma - fulfilling one's purpose; Artha - prosperity; Kama - desire, sexuality, enjoyment; and Moksha - enlightenment.