Orthopraxy is difficult to define for Hinduism, not because there is no mention of what constitutes right action, but rather because there is such diversity within Hinduism that it becomes difficult—if not impossible—to say anything definitive about the tradition as a whole. For any practice that might be considered "right practice" within Hinduism, there are usually a few traditions for which it is either irrelevant or even "wrong practice" (heteropraxy). Yet whatever diversity there is pertaining to practice, there is still more diversity pertaining to belief. For example, some Hindus believe in one god, others believe in many gods, and still others believe in no gods at all; yet, within Hinduism, none of these beliefs necessarily renders a person unorthodox. Indeed, Hindus have at times demonstrated a remarkable pluralism with respect to belief (although variations in belief have often been seen as inferior alternatives), but have tended to identify themselves and their tradition with the rites and practices that underlie Hindu society.
Perhaps the most consistent trait of Hindus is that some relation to the Vedic texts plays an important role in their religious and cultural lives. Hindus tend to distinguish between two broad groups: the astika (those who accept the authority of the Vedas) and nastika (those who do not accept the authority of the Vedas). It should be noted that such acceptance says nothing about what beliefs a person or group holds, but rather whether they are participating in the preservation and enrichment of Hindu society as inaugurated in the Vedas. Thus, "orthoprax" Hindus are considered astika, while Buddhists, Jainas, and Carvakas (those who reject the tradition stemming out of the Vedas) are considered nastika. The Vedic tradition is ultimately a belief in the dharma revealed by the Vedas—the cosmic order of reality that, when embodied in the structure of Hindu society, leads to social and cosmic harmony.
The most basic exemplification of the dharma is proper observation of caste distinctions (although there are additional distinctions made according to age, social position, etc.). Within Hindu thought, caste distinctions are not artificial constructs, but natural designations: one is born into a particular caste because of karmic residue from past lives. Moreover, society functions well only when these distinctions are respected, because each caste was created with particular capacities that correspond to particular needs within society. Traditionally, Brahmans—typically seen as the highest caste—are priests and scholars, kshatriyas are warriors and rulers, vaishyas are merchants and artisans, and shudras are farmers and laborers (the so-called untouchables typically fall outside of the caste system, and are seen as even lower than the shudras). Right practice for a Hindu is thus a matter of living according to one's caste and performing the duties and obligations of that caste (that is, living according to the dharma); however, because those duties and obligations are often different for each caste, what constitutes right practice for any Hindu is typically dependent on their caste (as well as a number of other related social considerations). Needless to say, caste intermarriage and attempts at social mobility have traditionally been censured within Hinduism.
Just as there are exceptions to the aforementioned adherence to the tradition stemming out of the Vedas, so there are other, less central practices that are widespread among Hindus (for example, reverence for the cow, refraining from harming other creatures, etc.). Furthermore, there are a number of dharmashastras (texts of religious laws) and other post-Vedic literature that further specify right action with respect to rituals, caste relations, and personal discipline (e.g., the Manava Dharmashastra or Manusmrti, Laws of Manu). What all of these manifold specifications of practice have in common, however, is that they all exemplify the attempt to act in accordance with the dharma for one's position in life and to do so while accruing as little negative karma as possible. Thus, while the Vedas may not be in the forefront of every Hindu's understanding of "right action," they ultimately inform the traditions that make such action properly Hindu.
With the Brahman class at the head of the Hindu caste system, one would expect authority to reside with them for interpreting orthopraxy with respect to the dharma. Historically, Brahman scholars have in fact seen themselves as the protectors of the dharma and have argued in the courts of their rulers (typically kshatriya) for the preservation and enforcement of a social structure based on the Vedic rules and ritual practices. However, because there has traditionally been no prevailing institutional authority for Hinduism, such preservation and enforcement has typically been possible only at the level of broad social pressure. Moreover, any authority the Brahmans have for interpreting the dharma has been at least matched by the authority afforded to extraordinary devotees and saints of any caste for reinterpreting it. Perhaps the most prominent recent example of this is found in Mahatma Gandhi (1869–1948), who proposed a radical shift in the structure of Hindu society by renaming—and thus repositioning—the so-called untouchables (those who reside in India but fall outside of the caste system); he renamed them harijan, or "God's people," and gave them equal status among other Hindus in temples. As Gandhi's case illustrates, the authority for reinterpreting the dharma does not necessarily reside with social position (Gandhi was a member of the vaishya caste), but rather with the moral authority—usually understood in terms of devotion and service—to speak on behalf of the dharma.
In the end, orthopraxy is crucial to the understanding of Hinduism not because Hinduism entails no particular beliefs or because it makes no claims for orthodoxy; different traditions do espouse particular beliefs, and many will not hesitate to claim orthodoxy for those beliefs. Rather, orthopraxy is important for Hinduism because the commonality of practices among Hindus far exceeds the commonality of beliefs. Indeed, it is not merely religious scholars but also Hindus themselves who define Hindu identity in terms of practices more than beliefs. This emphasis on practice rather than belief runs counter to the typical Western model of religions, but it is an emphasis that proves characteristic not only of Hinduism but also of Asian religious and social traditions generally.