My understanding is that caste is not a legitimate Hindu concept and that it is varna instead. From what I’ve read, varna is like the division of labour within society, but my question is, why was varna a formal system? Surely if we let people go about their business they will sort themselves out in each category? (the religious/intelligent become brahmin, etc).
I remember in the Bhagavad Gita that Sri Krishna had said he had split society in its 4 (I think) divisions.
Was there any benefits to formalising it? Is my assumption of it being a formal system even correct? Why was it formalised and why is it a necessary thing?