Religion in India
Religion in India is characterised by a diversity of religious beliefs and practices. India is a secular state with no state religion. The Indian subcontinent is the birthplace of four of the world's major religions; namely Hinduism, Buddhism, Jainism and Sikhism. Throughout India's history, religion has been an important part of the country's culture. Religious diversity and religious tolerance are both established in the country by the law and custom; the Constitution of India has declared the right to freedom of religion to be a fundamental right.
Islam and other religions
In the introduction to his "Indica", Biruni himself writes that his intent behind the work was to engage dialogue between Islam and the Indian religions, particularly Hinduism as well as Buddhism. Biruni was aware that statements about a religion would be open to criticism by its adherents, and insisted that a scholar should follow the requirements of a strictly scientific method. According to William Montgomery Watt, Biruni "is admirably objective and unprejudiced in his presentation of facts" but "selects facts in such a way that he makes a strong case for holding that there is a certain unity in the religious experience of the peoples he considers, even though he does not appear to formulate this view explicitly." Biruni argued that Hinduism was a monotheistic faith like Islam, and in order to justify this assertion, he quotes Hindu texts and argues that the worship of idols is "exclusively a characteristic of the common people, with which the educated have nothing to do."