The theory of caste is a part of spiritual anthropology in that it describes the basic tendencies of human nature and how they are related to one another, both in theory and in the context of the social order. What follows is precisely this type of study, and while human institutions, under normal conditions, attempt to retrace nature, they do so imperfectly and sometimes very imperfectly. Thus, we do not attempt to describe in detail or even justify the system of caste that is currently in place in modern India. What we say here is in accordance with the Hindu doctrine, but it may or may not apply to the social order of modern Hindu civilization. This does not alter the truth of the theory. A man might understand physics perfectly yet be unable to shoot an arrow into the bullseye of a target. Such is the discrepancy between principle and application, and in this age certain principles cannot be applied with any degree of success under present conditions.