Sri Aurobindo
Letters of Sri Aurobindo
Volume I - Part 4
The view taken by the Mahatma in these matters [of caste] is Christian rather than Hindu – for the Christian, self-abasement, humility, the acceptance of a low status to serve humanity or the Divine are things which are highly spiritual and the noblest 
privilege of the soul. This view does not admit any hierarchy of castes; the Mahatma accepts castes but on the basis that all are equal before the Divine; a Bhangi doing his dharma is as good as the Brahmin doing his, there is division of function but no hierarchy of functions. That is one view of things and the hierarchic view is another, both having a standpoint and logic of their own which the mind takes as wholly valid but which only corresponds to a part of the reality. All kinds of work are equal before the Divine and all men have the same Brahman within them, is one truth, but that development is not equal in all is another. The idea that it needs special punya to be born as a Bhangi is of course one of those forceful exaggerations of an idea which are common with the Mahatma and impress greatly the mind of his hearers. The idea behind is that his function is an indispensable service to the society, quite as much as the Brahmin’s, but that being disagreeable it would need a special moral heroism to choose it voluntarily and he thinks as if the soul freely chose it as such a heroic service and as a reward of righteous acts – that is hardly likely. The service of the scavenger is indispensable under certain conditions of society, it is one of those primary necessities without which society can hardly exist and the cultural development of which the Brahmin life is part could not have taken place. But obviously the cultural development is more valuable than the service of the physical needs for the progress of humanity as opposed to its first static condition and that development can even lead to the minimising and perhaps the eventual disappearance by scientific inventions of the need for the functions of the scavenger. But that I suppose the Mahatma would not approve of as it is machinery and a departure from the simple life. In any case it is not true that the Bhangi life is superior to the Brahmin life and the reward of especial righteousness. On the other hand the traditional conception that a man is superior to others because he is born a brahmin is not rational or justifiable. A spiritual or cultured man of Pariah birth is superior in the divine values to an unspiritual and worldly-minded or a crude and uncultured Brahmin. Birth counts, but the basic value is in the man himself, the soul behind, 
and the degree to which it manifests itself in his nature.