Thakns for your question Alan:) Diversity has strengthened our society-Indian. I've posted this already to another different question.We Indians have the most diversified society in the world-more than 2000 languages, 3000 different tribes and castes, 30 different states, each one with its own identity, n-number of differences.Still we are known for the unity of our country.

What sort of diversity? In what areas? And how much? There has to be something "common" to a society's members other than just where they live for it to be a society in any sense of the word. In other words, there must be something significant common to all its members that makes them think of themselves as "US" and as everybody outside their society as "THEM". Without that, there's no cohesion, no identity, and thus no society. The corollary of this is that "all societies are founded upon intolerance," (G.B. Shaw) and you can't have a society without it. While a broad cross section of views and experiences (if used and marshalled appropriately united toward a common vision and cause) may avoid "group-think", that doesn't mean that any and all diversity automatically guarantees some optimal hybrid solution or synergistic creativity. It can simply produce a Babel ... or a Bosnia. By way of example, one group of people whose prior culture and nature has instilled in them a view of government as a necessary evil, but only a hired agent, necessarily subserviant to the people, that's only authority (for using force) is to protect the life and limb and property of citizens from criminals, are not going to even be able to form any kind of al society/community with a group of people whose culture and nature has instilled in them the idea that government is the head of the body-politic, and that the people are just organs and limbs, deriving their entire worth and identity from the state, and that the government should order and take care of everything. In this case, if both groups are essentially equal in numbers and/or strength, one can't even say that this diversity weakens the whole, since there isn't even a whole, just 2 intractractably opposed and inimical societies, forced together like a dog and cat grafted together at the nose. You might as well ask a group of radical Lesbian feminists to build a commune with Bedoin Moslem Fundamentalists. You won't improve their chances by adding a contingent of Jews (Liberal, Conservative, and Orthodox), French Cartesians, Trotskyites, Maoists, Siciliian Mafiosos, Hindus of the professional caste, Rednecks, and urban American WASPS to the mix. You'd basically be embracing "cutlural diversity" by encouraging (even requiring!) everyone to drive on whichever side of the road they do in their own "old country" and follow all the traffic laws and driving etiquette from the same. While your at it, everyone should only speak their own personal language, and no one should be allowed to try to teach anyone else to speak it, for that would be an act of personal cultural imperialism.

strengthen

It can do either. It is part of what defines a society.