Why can't the world be united into one civilized and peaceful society?

It's all about the money, yes sir. All economic interests. Money rule the world. Do you think that the most powerful countries would agree to be considered the same with the poorest ones without getting anything? And nowadays the power of a state consits on its economic resources. Look at the EU and you'll find the answer. I live in a poor country and everybody around here is moritified because if my country will enter the EU all the prices will raise and the salaries will remain the same. A peaceful society would be one where money doesn't exist.

Here's a short answer: Because so many cultures with many different religions, beliefs and laws, tend to not like eachother so much and regard one another as heathens. Therefore, there is no compromise, because no one can see eye to eye. Basically it used to be about the strongest nation conquering the weaker ones and assimilating them into their own cultures. But we can't do that anymore. But human nature to "protect ourselves and our own" basically makes it difficult for such a thing to be possible. Besides the fact that some nations, or rather groups of people within nations, really do NOT want what you propose. Not everyone wants peace, despite what the newspapers declare.

Because Germans don't want to be Japanese, Italians don't want to be Somalians, etc. Whatever society, or civilization that would dominate the world, would discriminate, or eliminate all the others. I want the world to be peaceful, and civilized. But I don't want this country to be assimilated. Nor do I want this country to assimilate any other cultures. The U.S. has enough melting go on in it's pot now.

Because each one has his own dreams and aspirations of aquiring power.Now power is a strong motivator.As long as the desire for power is active the world can never be united into one civilized and peaceful society.

Good luck.

My opinion is because there are too many cultural and religious difference among people in the world. Until those things are better understood and accepted unilaterally, there will never be peace.

Human nature is to keep "progressing" towards atrophy. We think we are bettering things but in the long run we seem to be only out for ourselves.

Because most people don't know the Truth.

cause it would be boring.