The real Indian caste system

I know a Singaporean who comes from an Indian background, who shared some info from a Singapore newspaper about what India's caste system really is supposed to be:

Originally known as the varnashrama system, it comprises four broad scientific occupational divisions in society - the educator class, the administrator class, the entrepreneur class and the worker class - where everyone has the opportunity to take up an occupation befitting his or her natural tendencies and qualifications. This is based on the psychological propensity and character of the individual, and not on birth.

The writer also said that the classes worked together, which really should happen in any society. I'm just glad the US doesn't have caste system. That would make life quite rigid and seem more unfair than it sometimes is.