The Hart model for caste origin, writes Samuel, envisions "the ancient Indian society consisting of a majority without internal caste divisions and a minority consisting of a number of small occupationally polluted groups".
For example, for some early European documenters it was thought to correspond with the endogamous varnas referred to in ancient Indian scripts, and its meaning corresponds in the sense of estates.
To later Europeans of the Raj era it was endogamous jatis, rather than varnas, that represented caste, such as the 2378 jatis that colonial administrators classified by occupation in the early 20th century. The name stuck and became the usual word for the Hindu social group.
Social unrest during the 1920s led to a change in this policy.
From then on, the colonial administration began a policy of positive discrimination by reserving a certain percentage of government jobs for the lower castes.
The first three groups, Brahmins, Kshatriyas and Vaishya have parallels with other Indo-European societies, while the addition of the Shudras is probably a Brahmanical invention from northern India.
Scholars have questioned the varna verse in Rigveda, noting that the varna therein is mentioned only once.
Arvind Sharma, a professor of comparative religion, notes that caste has been used synonymously to refer to both varna and jati but that "serious Indologists now observe considerable caution in this respect" because, while related, the concepts are considered to be distinct. In attempting to account for the remarkable proliferation of castes in 18th- and 19th-century India, authorities credulously accepted the traditional view that by a process of intermarriage and subdivision the 3,000 or more castes of modern India had evolved from the four primitive classes, and the term 'caste' was applied indiscriminately to both varna or class, and jati or caste proper.
This is a false terminology; castes rise and fall in the social scale, and old castes die out and new ones are formed, but the four great classes are stable.
Thus, "Caste" is not an accurate representation of jati in English.