However, the now-popular claim that Sikhism is caste-free and that this sets it apart from Hinduism (on the assumption that caste is intrinsic to Hinduism), is simply untrue. Every Hindu knows that Sikhs have not ceased practising caste, but for an authoritative refutation, we may turn to a historian (W.H. McLeod) who scrutinized the record of Sikhism: The acknowledgement of caste identities was presumably acceptable to the Gurus, for the Gurus themselves married their own children according to traditional caste prescriptions. The anti-caste thrust of the Gurus teachings must be seen as a doctrine which referred to spiritual deliverance and a firm rejection of injustice or hurtful discrimination based on caste status. What is not implied is a total obliteration of caste identity.
There is enough of a prima facie case that Sikhism is a Hindu sect pure and simple. And effectively, some Sikhs do claim that they are Hindus. If we accept the historical definition of "Hindu" given by the Muslims, there is simply no doubt about it: all Sikhs fall under the heading "Indian Pagans", for they are neither Muslims nor Christians, Jews or Parsis. So, Sikhs are Hindus. Unless.
Unless Sikhs are some kind of Muslims. Ram Swarup starts his survey of the genesis of Sikh separatism with the discovery that T.P. Hughes' Dictionary of Islam, written in the British-Indian colonial context, devotes the third-longest of its articles (after Muhammad and Qurân) to the lemma Sikhism. According to Ram Swarup, it must be a strange sect of Islam where the word "Mohammed" does not occur even once in the writings of its founder, Nanak. Nor did later Gurus include the praise of Mohammed in the Guru Granth.
Most things in Sikhism can be traced either to Hindu origins or to borrowings from Islam. But for centuries, one thing which put the Sikhs firmly in the Hindu camp was the continuous hostility with the Islamic Empire of the Moghuls and with the Muslim Afghans. After Partition, there were practically no Muslims left in East Panjab, and the contrast with Hinduism could now receive the full emphasis for the first time. In that context, separatist Sikhs resorted to highlighting existing or introducing new elements borrowed from Islam. It is typical that in his overview of the elements which make up Sikh identity, Khushwant Singh overlooks specific Sikh commandments which set Sikhism apart from Islam, e.g. the prohibition on marrying Muslim women and on eating halâl meat.
That the Sikhs 'regarded themselves as Hindus' is confirmed by Khushwant Singh, who concedes that three centuries of Sikh history after Nanak, including the creation of the Khalsa as a Sikh martial vanguard by Guru Govind Singh, were not enough to make Sikhism into a separate religion: However, what is worthwhile to bear in mind is that, despite these innovations, this new community, the Khalsa Panth, remained an integral part of the Hindu social and religious system. It is significant that when Tegh Bahadur was summoned to Delhi, he went as a representative of the Hindus. He was executed in the year 1675. His son who succeeded him as guru later described his father's martyrdom as in the cause of the Hindu faith, to preserve their caste marks and their sacred thread did he perform the supreme sacrifice. The guru himself looked upon his community as an integral part of the Hindu social system.
In most indo-Aryan languages, the oft-used honorific mode of the singular is expressed by the same pronoun as the plural (e.g. Hindi unkâ, "his" or "their", as opposed to the non-honorific singular uskâ), and vice-versa; by contrast, the singular form only indicates a singular subject. The phrase commonly translated as 'the Lord preserved their tilak and sacred thread' (tilak-janjû râkhâ Prabh tâ-kâ), referring to unnamed outsiders assumed to be the Kashmiri Pandits, literally means that He "preserved b is tilak and sacred thread", meaning Tegh Bahadur's; it is already unusual poetic liberty to render "their tilak and sacred thread" this way, and even if that were intended, there is still no mention of the Kashmiri Pandits in the story. This is confirmed by one of the following lines in Govind's poem about his father's martyrdom: He suffered martyrdom for the sake of his faith.
In theory, the case for the basic Hindu identity of Sikhism is overwhelming. Unlike Jainism and Buddhism, Sikhism has gone through all the developments of Hinduism until the Moghul period. It has no separate theology or philosophy, no separate ethics or social structure. It has borrowed elements from Islam, but not the decisive ones: belief in a notion of a true God versus false gods, hence in iconoclasm, and belief in a monopolistic prophethood. There is nothing in Sikhism at which a Hindu should feel offended.