Hinduism is diverse at every level, extending beyond the threefold division into Vaishnavism, Shaivism and Shaktism (centred on complexes of deities associated with Vishnu, Shiva and Shakti/Mahadevi/the Goddess respectively) to encompass a multitude of sects and cults, ranging from elite perspectives of monastic study and reflection to folk practices of ritual possession, alongside change over time including the profusion of modern and contemporary movements and the worship of innumerable village or guardian deities in specific localities. This leads some commentators to point to Hinduisms in the plural rather than Hinduism in the singular. Certainly, it is very difficult to suggest what unifies Hinduism.
As the standard of orthodoxy, acceptance of the authority of the Veda, the most ancient sacred texts, has been proposed as a defining characteristic but acceptance may be merely nominal and some movements that are obviously Hindu, for example, the Virashaivas, reject it entirely. Another candidate for unifying Hinduism, closely connected to the Veda, is the role of brahmins (priests) as sacred specialists with ritual and textual expertise but there are other sacred specialists such as shamans, who provide necessary services like healing in folk traditions, and Hindu groups, like the reform movement founded by Narayana Guru from a Keralan dalit (outcaste) community, that challenge brahmanic dominance. Others suggest that the concepts of karma (law of action), samsara (round of existence), punarjanma (reincarnation) and moksha (liberation) unite Hindus, but these are also found in other religions of Indian origin and also do not necessarily reflect everyday Hindu experience which may focus upon living this life well rather than seeking moksha.
Membership of castes (individual hereditary social groups called jatis frequently related to the general hierarchical principle of social organisation established by the four great classes or varnas) has been cited as crucial but caste in the sense of jati is observed in some form by non-Hindus too, while Hindus are divided on the subject with some actively opposing it in whole or part and others denying any association between Hinduism and caste at all. Reverence for India as the sacred motherland has also been suggested as unifying Hinduism but, in addition to the controversial nationalist aspects of the cult of Bharat Mata (Mother India), the growing generations of Hindus living in diaspora can come to understand their relationship with India in different ways and locate the sacred in spaces nearer at hand. These difficulties explain why reference is made more generally to a sense of shared heritage giving rise to a shared identity, though this does not really explain from where this sense originates.
An approach that has been adopted by some scholars, which gets away from the expectation that a common core and clear boundaries are required to define Hinduism, is to apply what is called the ‘family resemblance’ model. No one feature is shared by all Hindus, but a range of features are connected by a set of overlapping similarities that edge off into other religions. This captures the rich diversity of Hinduism within the broader context of Indian religions, and allows us to continue to use the term as a convenient shorthand while recognising its limitations.