I saw someone answering a question on a forum suggesting that it will only be when people use their hearts and not their minds that the world will unite. I was instantly sure that this was the wrong way round as the things which cause friction seem to me to be deeply emotional – feelings of nationalism (even patriotism because presumably in a united world there will be no countries) feelings about religious belief, about ties to family and the oldest of them all, chauvinism. The very things that cause us to fight are in fact not very intellectual although since we have minds we can intellectualize them.
On the other hand the whole idea of a united world is one of rational thought which wants to get out of the chaos of war and enmity. The deep thoughts that have been given by political theorists to social matters, about how countries should treat each other and how people should be pluralistic are all about getting over emotions that divide and instilling emotions that unite.
And that’s the point. Whatever we do we are human, and our feelings will always be involved but feelings can be educated. It is as easy to teach people to feel passionate about being fair, as it is to teach them to be materialist and avaricious.